Myth and Truth on the Emperor Constantine

There are two mainstream views of the Emperor Constantine. For some, Constantine is called a Saint, or at the very least he is held in high regard, since his reign is said to have helped spread Christianity by making it legal.   Added to this is the fact that he presided over the Council of Nicea.

The other view is that he was a pagan Emperor who introduced pagan practices such as Christmas, the Trinity and Easter into Christianity. Whichever side you are on, below are facts about Constantine that may center your perspective to a more historical and factual side:

1. Constantine did not “paganize” Christianity with practices such as Easter and Christmas

We have previously wrote on the myths that Christmas and Easter comes from paganism. There is an abundance of evidence proving both these myths false. For more in depth on this please see those post here and here. In short, the date of December 25th for Jesus’ birth is rooted in the early Church long before Constantine and was not related to any pagan deity before Jesus’ time.

The same can be said of the word Easter.

So no Constantine did not bring pagan practices into the Church when it comes to Christmas and Easter.

2. Constantine and the Council of Nicea did not create the New Testament Canon or the Trinity

No matter what is claimed, Constantine did not literally establish the New Testament canon. Early Christians preserved the New Testament, long before Constantine’s time. You can read about which books were accepted among the Early Church Fathers in text such as the Muratorian Canon (200 A.D.) and a similar list by Origen (240 A.D), which was made known by Eusebius (300 A.D) (see bible-researcher.com and ntcanon.org). Additionally, the writings of the Church Fathers—Clement of Rome, Ignatius, Polycarp, et al.— quote so much of the New Testament that it is preserved in their writings:

Bruce Metzger, an American Biblical scholar, said this about their writings:

“Indeed, so extensive are these citations that if all other sources for our knowledge of the text of the New Testament were destroyed, they would be sufficient alone in reconstructing practically the entire New Testament.” [1]

The claim that Constantine brought the doctrine of the trinity over from paganism is also myth. This one is popular among Hebrew Rooters, Muslims, and sects like Jehovah Witnesses.  The doctrine of the Trinity is clearly in the Bible text.  And the word Trinity, is in the writings of the early Church in the centuries before Constantine and the Council of Nicea:

In like manner also the three days which were before the luminaries, are types of the Trinity, of God, and His Word, and His wisdom. ~ Theophilus, Theophilus to Autolycus, Book II, Ch. 15

As if in this way also one were not All, in that All are of One, by unity (that is) of substance; while the mystery of the dispensation is still guarded, which distributes the Unity into a Trinity, placing in their order the three Persons—the Father, the Son, and the Holy Ghost: three, however, not in condition, but in degree; not in substance, but in form; not in power, but in aspect; yet of one substance, and of one condition, and of one power, inasmuch as He is one God, from whom these degrees and forms and aspects are reckoned, under the name of the Father, and of the Son, and of the Holy Ghost. ~ Tertullian, Against Praxeas, Ch. 2

From all which we learn that the person of the Holy Spirit was of such authority and dignity, that saving baptism was not complete except by the authority of the most excellent Trinity of them all, i.e., by the naming of Father, Son, and Holy Spirit. ~ Origen, De Principiis, Book I, Ch. 3, Section 2

Constantine and the Council of Nicaea only wrote out what was already written and established by Christians before them.

3. Constantine did in some way “paganize” Christianity with Temples, Shrines and Altars

This is actually true. Constantine tolerated all religions on and off during his reign as Emperor. The empire still used coins depicting Sol Invictus. According to pagan historian Zosimus, Constantine had statues of Apollos erected along with those of other gods.

This era is also when the Church began building temples with altars, using incense, and many other rituals that exist in some churches today. Not that we are trying to condemn those who have such practices. However, worship up until the time of Constantine was rather simple, with Christians usually meeting in private homes and occasionally in cemeteries (Roman catacombs) to honor the martyrs. Justo Gonzalez, in The Story of Christianity: The Early Church to the dawn of the Reformation, gives us insight into a few changes in worship came about with Constantine:

After Constantine’s conversion, Christian worship began to be influenced by imperial protocol. Incense, which was used as a sign of respect for the emperor, began appearing in Christian churches. Officiating ministers, who until then had worn everyday clothes, began dressing in more luxurious garments—and soon were called “priests,” in imitation of their pagan counterparts, while the communion table became an “altar”—in opposition to the instructions found earlier in the Didache. Likewise, a number of gestures indicating respect, which were normally made before the emperor, now became part of Christian worship…Eventually, the congregation came to have a less active role in worship. [2]

The problem that arises with this is that most of these changes had been written against by the early Church Fathers:

…but who still, not less even than the most ignorant, run after their images, and temples, and famous mysteries; and seeing this, He has chosen the foolish things of this world — the simplest of Christians, who lead, however, a life of greater moderation and purity than many philosophers— to confound the wise, who are not ashamed to address inanimate things as gods or images of the gods. For what reasonable man can refrain from smiling when he sees that one who has learned from philosophy such profound and noble sentiments about God or the gods, turns straightway to images and offers to them his prayers, or imagines that by gazing upon these material things he can ascend from the visible symbol to that which is spiritual and immaterial. ~ Origen, Contra Celsus, Book VI, Chapter 44

…if we describe as lame and mutilated in soul those who run to the temples as to places having a real sacredness and who cannot see that no mere mechanical work of man can be truly sacred ~ Origen, Contra Celsus, Book VI, Chapter 52

…You shall have no other gods before Me: you shall not make unto you any graven image, or any likeness of anything that is in heaven above, or that is in the earth beneath,…you shall not bow down yourself to them…It is in consideration of these and many other such commands, that they (Christians) not only avoid temples, altars, and images, but are ready to suffer death when it is necessary, rather than debase by any such impiety the conception which they have of the Most High God. ~ Origen, Contra Celsus, Book VI, Chapter 64

But do you think that we conceal what we worship, if we have not temples and altars? And yet what image of God shall I make, since, if you think rightly, man himself is the image of God? What temple shall I build to Him, when this whole world fashioned by His work cannot receive Him? And when I, a man, dwell far and wide, shall I shut up the might of so great majesty within one little building?  ~ Octavius (Minucius Felix)

…because we do not rear temples for the ceremonies of worship, do not set up statues and images of any god, do not build altars, do not offer the blood of creatures slain in sacrifices, incense, nor sacrificial meal, and finally, do not bring wine flowing in libations from sacred bowls ~ Arnobius, Against the Heathen, Book VI

We are not arguing that Christian images or buildings are somehow wrong, but we are showing that they were not required by the early Church either and should not be venerated.

Beginning with the conversion of Constantine a great change occurred in this understanding of the Church building and its significance….The Church building was gradually freed from subordination to its eccelsiological meaning, aquired its own independent significance, and the center of attention was shifted from the Church assembled and realized within the building itself, as in fact a sanctified building or sanctuary… This was a church-sanctuary, a place for the habitation and residence of the sacred, therefore capable of sanctiying and communicating the sacred to whoever entered it… On the one hand there was the Christian reception of the heroon or temple memorial raised over the tomb of a martyr or saint, or at the place of his theopany. On the other
and there was the basillica, the place for public assembly or state cult. Both forms gradually merged, but characteristically their merger took on the form of the hero’s temple or sanctuary… ~Alexander Schmemann’s Introduction to Liturgical Theology,

Philip Schaff wrote on the history of the veneration of Martyrs or Saints in the Early Church and how this was
changed after Constantine:

In the first three centuries the veneration of the martyrs in general restricted itself to the thankful remembrance of their virtues and the celebration of the day of their death as the day of their heavenly birth. This celebration usually took place at their graves. So the church of Smyrna annually commemorated its bishop Polycarp, and valued his bones more than gold and gems, though with the express distinction: ‘Christ we worship as the Son of God; the martyrs we love and honor as disciples and successors of the Lord, on account of their insurpassable love to their King and Master, as also, we wish to be their companions and fellow disciples.’

Here we find this veneration as yet in its innocent simplicity. But in the Nicene age it advanced to a formal invocation of the saints as our patrons (patroni) and intercessors (intercessores, mediatores) before the throne of grace, and degenerated into a form of refined polytheism and idolatry. The saints came into the place of the demigods, Penates and Lares, the patrons of the domestic hearth and of the country. As once temples and altars to the heroes, so now churches and chapels came to be built over the graves of the martyrs, and consecrated to their names (or more precisely to God through them). People laid in them, as they used to do in the temple of Aesculapius, the sick that they might be healed, and hung in them, as in the temples of the gods, sacred gifts of silver and gold. Their graves were, as Chrysostom says, move splendidly adorned and more frequently visited than the palaces of kings.

Banquets were held there in their honor, which recall the heathen sacrificial feasts for the welfare of the manes. Their relics were preserved with scrupulous care, and believed to possess miraculous virtue. Earlier, it was the custom to pray for the martyrs (as if they were not yet perfect) and to thank God for their fellowship and their pious example. Now such intercessions for them were considered unbecoming, and their intercession was invoked for the living. This invocation of the dead was accompanied with the presumption that they take the deepest interest in all the fortunes of the kingdom of God on earth, and express it in prayers and intercessions

But in spite of all these distinctions and cautions, which must be expected from a man like Augustine, and acknowledged to be a wholesome restraint against excesses, we cannot but see in the martyr-worship, as it was actually practised, a new form of the hero-worship of the pagans.

Nor can we wonder in the least. For the great mass of the Christian people came, in fact, fresh from polytheism, without thorough conversion, and could not divest themselves of their old notions and customs at a stroke. The despotic form of government, the servile subjection of the people, the idolatrous homage which was paid to the Byzantine emperors and their statues, the predicates divina, sacra, coelestia, which were applied to the utterances of their will, favored the worship of saints.

The heathen emperor Julian sarcastically reproached the Christians with reintroducing polytheism into monotheism, but, on account of the difference of the objects, revolted from the Christian worship of martyrs and relics, as from the “stench of graves and dead men’s bones.”

The Manichaean taunt we have already mentioned. The Spanish presbyter Vigilantius, in the fifth century, called the worshippers of martyrs and relics, ashes-worshippers and idolaters, and taught that, according to the Scriptures, the living only should pray with and for each other.

Even some orthodox church teachers admitted the affinity of the saint-worship with heathenism, though with the view of showing that all that is good in the heathen worship reappears far better in the Christian. Eusebius cites a passage from Plato on the worship of heroes, demi-gods, and their graves, and then applies it to the veneration of friends of God and champions of true religion; so that the Christians did well to visit their graves, to honor their memory there, and to offer their prayers.

The Greeks, Theodoret thinks, have the least reason to be offended at what takes place at the graves of the martyrs; for the libations and expiations, the demi-gods and deified men, originated with themselves. Hercules, Aesculapius, Bacchus, the Dioscuri, and the like, are deified men; consequently it cannot be a reproach to the Christians that they—not deify, but—honor their martyrs as witnesses and servants of God.

The ancients saw nothing censurable in such worship of the dead. The saints, our helpers and patrons, are far more worthy of such honor. The temples of the gods are destroyed, the philosophers, orators, and emperors are forgotten, but the martyrs are universally known. The feasts of the gods are now replaced by the festivals of Peter, Paul, Marcellus, Leontius, Antonins, Mauricius, and other martyrs, not with pagan pomp and sensual pleasures, but with Christian soberness and decency.

In connection with the new hero-worship a new mythology also arose, which filled up the gaps of the history of the saints, and sometimes even transformed the pagan myths of gods and heroes into Christian legends. The superstitious imagination, visions, and dreams, and pious fraud famished abundant contributions to the Christian legendary poesy.

The worship of the saints found eloquent vindication and encouragement not only, in poets like Prudentius (about 405) and Paulinus of Nola (died 431), to whom greater freedom is allowed, but even in all the prominent theologians and preachers of the Nicene and post-Nicene age. It was as popular as monkery, and was as enthusiastically commended by the leaders of the church in the East and West.

The two institutions, moreover, are closely connected and favor each other. The monks were most zealous friends of saint-worship in their own cause. The church of the fifth century already went almost as far in it as the Middle Age, at all events quite as far as the council of Trent; for this council does not prescribe the invocation of the saints, but confines itself to approving it as “good and useful” (not as necessary) on the ground of their reigning with Christ in heaven and their intercession for us, and expressly remarks that Christ is our only, Redeemer and Saviour.

This moderate and prudent statement of the doctrine, however, has not yet removed the excesses which the Roman Catholic people still practise in the worship of the saints, their images, and their relics. The Greek church goes even further in theory than the Roman; for the confession of Peter Mogilas (which was subscribed by the four Greek patriarchs in 1643, and again sanctioned by the council of Jerusalem in 1672), declares it duty and propriety (χρέος) to implore the intercession (μεσιτεία) of Mary and the saints with God for us. -Philip Schaff

The church building in the early Church was nothing more than a place for the gathering of the Church (the believers). The church building had no sacred value, no holy relics and no altars. I

4. Constantine’s reign changed church Structure and Political Involvement

Constantine himself may not have altered this, however the Church under him did.

The Eastern Orthodox and Roman Catholic Churches claim that Constantine changed many things because he was guided by the Holy Spirit. This includes vested hierarchs, such as Cardinals or Metropolitans, Bishops, Patriarchs and Popes, despite the fact that in the early Church there was only Presbyters (Bishops) and Deacons. Furthermore, apostolic succession in the early Church only involved the keeping of apostolic teaching and tradition.

Prior to Constantine, the early Church was also not involved in politics. During and after Constantine, Imperial edicts began being established that would lead to a tax exemption for the bishops and hierarchs of the church. Not only this, but they were also exempt from military conscription, and from the labor of public works that others were forced to do. While it sounds good on the surface, Gonzalez points out that “the new privileges, prestige and power now granted to church leaders soon led to acts of arrogance and even to corruption.”[4] With this power came what is known as “simony,” or “the buying or selling of a church office or ecclesiastical preferment.”[5] So instead of the church being ran by all believers who kept in line with apostolic teaching and tradition, positions were now being purchased by men with the most money. This went completely against how the earlier Church had functioned.

Acts 4:34, 35:

³⁴ Neither was there any among them that lacked: for as many as were possessors of lands or houses sold them, and brought the prices of the things that were sold, ³⁵ And laid [them] down at the apostles’ feet: and distribution was made unto every man according as he had need. (KJV)

Constantine brought to the Church  a more aristocratic or monarchic form of Christianity. Some believe this was a good thing. Others saw the combining of the secular world with Christianity. In fact the word now used for hierarchs—clergy—comes from secular priesthoods. This structure would by the end of the 4th century rule the Roman Empire through the Church with hierarchs heavily involved in politics.

Another form of structure which was added to the Church by Constantine was the use of chanting during services. This was a custom of pagan temples as well as gold adornments.  Again, we are not attempting to condemn anyone who chants in their churches because we believe that the accusation of paganism is used too much nowadays. Even so, in some sense,  while Constantine did not “paganize” Christianity with Sunday worship or Holidays such as Christmas, he did “paganize” Christianity by Christianizing pagan temples, pagan priestly orders and social politics. All of which in some way has had negative effects in the long run as it has changed our perspective of what church is, what it means to be the church and it has blurred the lines between Jesus’ kingdom and those of this world.

5. Constantine had Christians exiled

Some churches, such as the Eastern Orthodox, title Constantine as “equal to the Apostles”, which is ridiculous since Constantine did not experience anything even close to what the Apostles experienced. He didn’t travel and spread the Gospel or suffer persecution as the Apostles and the early Christians did. In fact,  Constantine wasn’t even baptized until just before his death, something that the Apostles taught was required once faith in Jesus was professed. Being a professing Christian, Constantine partook of the Eucharist for quiet some years, however, not having been baptized, this was against the Didache (50 A.D):

But let no one eat or drink of this eucharistic thanksgiving, but they that have been baptized into the name of the Lord;

His baptism, which was performed on his deathbed nearly 25 years after his profession, was administered by Eusebius of Nicomedia, who was a follower of Arius, whom the Council of Nicaea had been held against. Because Constantine began to favor the Arian priest before his death, Athanasius was exiled several times, once by Constantine I and later by Constantine’s son.

The first exile of Athanasius under Constantine came in 335 and lasted until 337, when Athanasius was accused by a schismatic called Meletius of Lycopolis of wrongly treating the Arians and the Meletians for withholding grain and other things. Eusebius of Nicomedia (the Arian priest who later baptized Constantine) deposed Athanasius. Constantine had to rule on the matter when it was brought before him and ruled against Athanasius, banishing him into exile. This was only 10 years after the first Council of Nicaea.

Athanasius is a Saint in many churches including the Roman Catholic and Eastern Orthodox Churches. So one has to wonder why Constantine can be considered a Saint as well as Athanasius, even though Constantine had him banished during the last years of his life. At this point, Constantine had moved to the side of the Arians and had abandoned what had been defended in the first Council of Nicaea.  If Constantine was a true Christian he should have progressed towards salvation rather than dying as one who persecuted the Church.

6. Constantine and the church of his time both participated in murder

Constantine had his wife and son put to death because they did not live up to his moral standards, as well as having eunuchs murdered in Egypt. At least one Donatist Bishop was killed and many were exiled in the first “Christian” against Christian persecutions.  Some call this the first reformation,  because the Donatists refused to submit to the newly found authority of the Emperor who, for the first time in Christian history, did not separate the Church and the State. Constantine used military force against the Donatists and even ransacked their places of worship.

The Church had never murdered others before this time. They rebuked Judaizers and the Gnostics,  but they did not kill them or anyone for that matter. Military service was to be shunned by Christians of the early Church.

Constantine allowed priests who were traitors back into office.  However, the Donatists, whom Constantine persecuted, believed that priests should be a moral example just as Jesus and the Apostles were. It seems that Constantine defined morals based on his own ideas and favor towards others rather than on what the early Church had to say on the morals of priests:

Those, however, who are believed to be presbyters by many, but serve their own lusts, and, do not place the fear of God supreme in their hearts, but conduct themselves with contempt towards others, and are puffed up with the pride of holding the chief seat, and work evil deeds in secret, saying, No man sees us, shall be convicted by the Word, who does not judge after outward appearance (secundum gloriam), nor looks upon the countenance, but the heart;…. From all such persons, therefore, it behooves us to keep aloof, but to adhere to those who, as I have already observed, do hold the doctrine of the apostles, and who, together with the order of priesthood (presbyterii ordine), display sound speech and blameless conduct for the confirmation and correction of others. In this way, Moses, to whom such a leadership was entrusted, relying on a good conscience, cleared himself before God, saying, I have not in covetousness taken anything belonging to one of these men, nor have I done evil to one of them….In this way, too, Samuel, who judged the people so many years… saying, I have walked before you from my childhood even unto this day: answer me in the sight of God, and before His anointed (Christi ejus); whose ox or whose ass of yours have I taken, or over whom have I tyrannized, or whom have I oppressed? Or if I have received from the hand of any a bribe or [so much as] a shoe, speak out against me, and I will restore it to you... the people had said to him, You have not tyrannized, neither have you oppressed us, neither have you taken ought of any man’s hand…

In this strain also the Apostle Paul, inasmuch as he had a good conscience, said to the Corinthians: For we are not as many, who corrupt the Word of God: but as of sincerity, but as of God, in the sight of God speak we in Christ; 2 Corinthians 2:17 We have injured no man, corrupted no man, circumvented no man. 2 Corinthians 7:2…..Such presbyters does the Church nourish, of whom also the prophet says: I will give your rulers in peace, and your bishops in righteousness. Isaiah 60:17….. 1 Corinthians 12:28 Where, therefore, the gifts of the Lord have been placed, there it behooves us to learn the truth, [namely,] from those who possess that succession of the Church which is from the apostles, and among whom exists that which is sound and blameless in conduct, as well as that which is unadulterated and incorrupt in speech. For these also preserve this faith of ours in one God who created all things; and they increase that love [which we have] for the Son of God ~ Irenaeus, Against Heresies

Constantine’s son, Constantius II, went on to lead mass murders of Christian “heretics” as well as full support of Arians.

John Wesley was one of many Christians who could see through the myth that Constantine was beneficial to Christianity. While Constantine may have legalized what Christians were already doing, his new form of Christianity was not that of the Early Church and was instead used mostly for political gain:

Persecution never did, never could, give any lasting wound to genuine Christianity. But the greatest it ever received, the grand blow which was struck at the very root of that humble, gentle, patient love, which is the fulfilling of the Christian law, the whole essence of true religion, was struck in the fourth century by Constantine the Great, when he called himself a Christian, and poured in a flood of riches, honours, and power upon the Christians; more especially upon the Clergy. Then was fulfilled in the Christian Church, what Sallust says of the people of Rome: Sublata imperii aemula, non sensim, sed praecipiti cursu, a virtutibus descitum, ad vitia transcursum. [Mr. Wesley doubtless quoted from memory; and this accounts for the slight mistake into which he has here fallen. The passage referred to does not occur in Sallust, but in Velleius Paterculus, and reads thus: — Remoto Carthaginis metu, sublataque imperri aemula, non gradu, sed praecipiti cursu, a virtute descitum, ad vitia transcursum. Lib. ii. cap. 1. — Edit. ] Just so, when the fear of persecution was removed, and wealth and honour attended the Christian profession, the Christians “did not gradually sink, but rushed headlong into all manner of vices.” Then “the mystery of iniquity” was no more hid, but stalked abroad in the face of the sun. Then, not the golden but the iron age of the Church commenced: Then one might truly say, Protinus irrupit venae pejoris in aevum Omne nefas; fugere pudor, verumque fidesque, In quorum subiere locum fraudesque, dolique, Insidiaeque, et vis, et amor sceleratus habendi. At once, in that unhappy age, broke in All wickedness, and every deadly sin: Truth, modesty, and love fled far away, And force, and thirst of gold, claim”d universal sway,

28. And this is the event which most Christian expositors mention with such triumph! yea, which some of them suppose to be typified in the Revelation, by “the New Jerusalem coming down from heaven!” Rather say, it was the coming of Satan and all his legions from the bottomless pit: Seeing from that very time he hath set up his throne over the face of the whole earth, and reigned over the Christian as well as the Pagan world with hardly any control. Historians, indeed, tell us, very gravely, of nations, in every century, who were by such and such (Saints without doubt!) converted to Christianity: But still these converts practised all kinds of abominations, exactly as they did before; no way differing, either in their tempers or in their lives, from the nations that were still called Heathens. Such has been the deplorable state of the Christian Church, from the time of Constantine till the Reformation. A Christian nation, a Christian city, (according to the scriptural model,) was nowhere to be seen; but every city and country, a few individuals excepted, was plunged in all manner of wickedness. – John Wesley, The Mystery of Iniquity

We may step back above a thousand years from this, without finding any better time. No historian gives us the least intimation of any such, till we come to the age of Constantine the Great. Of this period several writers have given us most magnificent accounts. Yea, one eminent author, no less a man than Dr. Newton, the late Bishop of Bristol, has been at no small pains to show, that the conversion of Constantine to Christianity, and the emoluments which he bestowed upon the Church with an unsparing hand, were the event which is signified in the Revelation by “the new Jerusalem coming down from heaven!”

16. But I cannot, in anywise subscribe to the Bishop”s opinion in this matter. So far from it, that I have been long convinced, from the whole tenor of ancient history, that this very event, Constantine”s calling himself a Christian, and pouring in that flood of wealth and honour [power] on the Christian Church, the Clergy in particular, was productive of more evil to the Church than all the ten persecutions put together. From the time that power, riches, and honour of all kinds were heaped upon the Christians, vice of all kinds came in like a flood, both on the Clergy and laity. From the time that the Church and State, the kingdoms of Christ and of the world, were so strangely and unnaturally blended together, Christianity and Heathenism were so thoroughly incorporated with each other, that they will hardly ever be divided till Christ comes to reign upon earth. So that, instead of fancying that the glory of the new Jerusalem covered the earth at that period, we have terrible proof that it was then, and has ever since been, covered with the smoke of the bottomless pit. – John Wesley, Of Former Times

And as it was with them in ancient times, so it is with the present generation. Thousands of those who bear the name of Christ are now given up to an undiscerning mind. The god of this world hath so blinded their eyes, that the light cannot shine upon them; so that they can no more discern the signs of the times, than the Pharisees and Sadducee’s could of old. A wonderful instance of this spiritual blindness, this total inability to discern the signs of the times mentioned in Scripture, is given us in the very celebrated work of a late eminent writer; who supposes, the New Jerusalem came down from heaven, when Constantine the Great called himself a Christian. I say, called himself a Christian; for I dare not affirm that he was one, any more than Peter the Great. I cannot but believe, he would have come nearer the mark, if he had said, that it was the time when a huge cloud of infernal brimstone and smoke came up from the bottomless pit! For surely there never was a time wherein Satan gained so fatal an advantage over the Church of Christ, as when such a flood of riches, and honour, and power broke in upon it, particularly on the Clergy! 

8. By the same rule, what signs would this writer have expected of the approaching conversion of the Heathens He would doubtless, have expected a hero, like Charles of Sweden, or Frederick of Prussia, to carry fire, and sword, and Christianity, through whole nations at once! And it cannot be denied, that since the time of Constantine, many nations have been converted in this way. But could it be said concerning such conversions as these; “The kingdom of heaven cometh not with observation” Surely every one must observe a warrior rushing through the land, at the head of fifty or sixty thousand men! But is this the way of spreading Christianity, which the author of it, the Prince of Peace, has chosen Nay, it is not in this manner that a grain of mustard seed grows up into a great tree. It is not thus that a little leaven leavens the whole lump. Rather, it spreads by degrees farther and farther, till the whole is leavened. We may form a judgment of what will be hereafter, by what we have seen already. And this is the way wherein true Christian religion, the faith that worketh by love, has been spreading, particularly through Great Britain and its dependencies, for half a century.

Philip Schaff also wrote in great detail of Constantine and had this to say about Constantine’s version of Christianity:

“At all events Christianity did not produce in Constantine a thorough moral transformation. He was concerned more to advance the outward social position of the Christian religion, than to further it’s inward mission. He was praised and censured in turn by the Christians and the pagans, the Orthodox and the Arians, as they successively experienced his favor or dislike. He bears some resemblance to Peter the Great both in his public acts and in his private character by combining great virtues and merits with monstrous crimes” ~ From Constantine the Great to Gregory the Great, A.D. 311-600 By Philip Schaff

Here are a few more quotes on Constantine:

In the most deeply significant of the legends concerning Jesus, we are told how the devil took him up into a high mountain and showed him all the kingdoms of the world in a moment of time; and the devil said unto him: “All this power will I give unto thee, and the glory of them, for that is delivered unto me, and to whomsoever I will, I give it. If thou, therefore, wilt worship me, all shall be thine.” Jesus, as we know, answered and said “Get thee behind me, Satan!” And he really meant it; he would have nothing to do with worldly glory, with “temporal power;” he chose the career of a revolutionary agitator, and died the death of a disturber of the peace. And for two or three centuries his church followed in his footsteps, cherishing his proletarian gospel. The early Christians had “all things in common, except women;” they lived as social outcasts, hiding in deserted catacombs, and being thrown to lions and boiled in oil.
But the devil is a subtle worm; he does not give up at one defeat, for he knows human nature, and the strength of the forces which battle for him. He failed to get Jesus, but he came again, to get Jesus’ church. He came when, through the power of the new revolutionary idea, the Church had won a position of tremendous power in the decaying Roman Empire; and the subtle worm assumed the guise of no less a person than the Emperor himself, suggesting that he should become a convert to the new faith, so that the Church and he might work together for the greater glory of God. The bishops and fathers of the Church, ambitious for their organization, fell for this scheme, and Satan went off laughing to himself. He had got everything he had asked from Jesus three hundred years before; he had got the world’s greatest religion.
Upton Sinclair, in The Profits of Religion : An Essay in Economic Interpretation (1918), Book Seven : The Church of the Social Revolution, “Christ and Caesar”

From the time that the heads of government assumed an external and nominal Christianity, men began to invent all the impossible, cunningly devised theories by means of which Christianity can be reconciled with government. But no honest and serious-minded man of our day can help seeing the incompatibility of true Christianity — the doctrine of meekness, forgiveness of injuries, and love — with government, with its pomp, acts of violence, executions, and wars. The profession of true Christianity not only excludes the possibility of recognizing government, but even destroys its very foundations.
Leo Tolstoy, The Kingdom of God is Within You (1894), Ch. 10

After his victory at the Milvian Bridge, faithful to his promise, Constantine favors the church from which he has received support. Catholic Christianity becomes the state religion and an exchange takes place: the church is invested with political power, and it invests the emperor with religious power. We have here the same perversion, for how can Jesus manifest himself in the power of domination and constraint? We have to say here very forcefully that we see here the perversion of revelation by participation in politics, by the seeking of power. The church lets itself be seduced, invaded, dominated by the ease with which it can now spread the gospel by force (another force than that of God) and use its influence to make the state, too, Christian. It is great acquiescence to the temptation Jesus himself resisted, for when Satan offers to give him all the kingdoms of the earth, Jesus refuses, but the church accepts.
Jacques Ellul, The Subversion of Christianity (1982), G. Bromiley, trans. (1986), p. 124

Woe to the Christian Church when it will have been victorious in this world, for then it is not the Church that has been victorious but the world. Then the heterogeneity between Christianity and the world has vanished, the world has won, and Christianity has lost.
Søren Kierkegaard, Practice in Christianity (1850)

Conclusion

Myths of paganism carry both some truth when it comes to Constantine. However, in most cases Constantine only legalized what Christians had been doing all the way back to the first century and those practices were not related to paganism. In truth, pagans often copied what Christians were doing, such as Christmas.

In other cases, such is the case with imperialism, politics and extended church structure, Christianity did change due to Constantine, and this was not for the benefit of Christianity.