Constantine the Great was the first Christian emperor of Rome. By his adoption of Christianity, and by various policies encouraging its growth, he played a major role in transforming it from a persecuted sect into a dominant religion of Europe. Constantine was born about 280, in the town of Naissus (present day Nis) in what is now Yugoslavia. His father was a high-ranking army officer, and Constanstine spent his younger days in Nicomedia, where the court of the Emperor Diocletian was situated. Diocletian abdicated in 305, and Constantine's father, Constantius, became the ruler of the western half of the Roman Empire. When Constanstius died the following year, Constanstine was proclaimed emperor by his troops. Other generals, however, disputed his claim, and a series of civil wars followed. These ended in 312 when Constanstine defeated his remaining rival, Maxementius, at the Battle of the Milivian Bridge, near Rome. Constanstine was now undisputed ruler of the western half of the Empire; however, another general, Licinius, ruled the eastern half. In 323, Constanstine attacked and defeated Licinius also, and from then until his death in 337 was sole ruler of the Roman Empire. It is uncertain just when Constanstine became converted to Christianity. The most usual story is that on the eve of the Battle of the Milivian Bridge, Constanstine saw a fiery cross in the sky, together with the words "By this sign shalt thou conquer". Regardless of how or when he was converted, Constanstine became deeply dedicated to the advancement of Christianity. One of his early actions was the Edict of Milan, under which Christianity became a legal and tolerated religion. The Edict also provided for the return of Church property which had been confiscated during the preceding period of persecution, and it established Sunday as a day of worship. The Edict of Milan was not motivated by general feelings of religious toleration. On the contrary, Constanstine's reign may said to mark the begining of the official persecution of the Jews that was to persist in Christian Europe for so many centuries. Constanstine never established Christianity as the official state religion. However, by his legislation and other policies, he dis much to encourage it's growth. During hid reign it became obvious that converstion to Christianity enhanced one's prospects for promotion to a high government position, and his decrees gave the church various useful priviledges and immunities. Also, construction of several of the world's most famous church buildings-such as the Church of the Nativity in Bethlehelm, and the Church of the Holy Sepulchre in Jerusalem-was commenced during his reign. Constanstine's role as the first Christian emperor of Rome would by itself entitle him to a place on this list. However, several of his other actions have also had far-reaching consequences. For one thing, he rebuilt and greatly expanded the old city of Byzantium, renamed it Constantinople, and made it his capital. Constantinople( which is today called Istanbul) was to become one of the great cities of the world; it remained the capital of the Eastern Roman Empire until 1453, and for centuries thereafter was the capital of the Ottoman Empire. Constanstine also played a significant role in the internal history of the Church. To deal with dispute between the followers of Arius and Athanasius (two Christian theologians who advanced conflicting doctrines), Constanstine convoked the Council of Nicaea (in 325), the first general council of the Church. The council, in which Constanstine took an active part, resolved the dispute by its adoption of the Nicene Creed, which became orthodox Church doctrine. More important still was some of his civil legislation. Constantine introduced laws which made certain occupations (e.g., butchers, bakers) hereditary. He also issued a decree under which coloni (a class of tenent farmers) were forbidden to leave there land. In modern terms, this decree converted the coloni into serfs, permanently attached to land. This and similar legislation helped to lay the foundations for the entire social structure of medieval Europe. Constanstine chose not to be baptized until he was on his deathbed, but it is clear that he had been converted to Christianity long before that. It is equally plain that the spiritual content of Christianity had eluded him completely. Even by the standards of the day, he was ruthless and cruel-and not merely to his enemies. For reasons that are unclear, he had his wife and his eldest son put to death in 326. It might be argued that Constanstine's adoption of Christianity did not really change the course of history, but merely ratified the inevitable. After all, although the Emperor Diocletian(who ruled 284-305) had conducted a vigorous persecution of Christianity, his attempt to suppress the religion was unsuccessful, for by that time Christianity was far too strong to be stamped out by even the fiercest measures. When one considers the failure of Diocletians's efforts to extirpate Christianity, one suspects that Christianity might eventually have triumphed even without Constanstine's intervention. Such speculations are interesting, but inconclusive. It is hard to be sure what might have happened without Constanstine. It is quite plain, though, that with his encouragement, Christianity rapidly expanded in both numbers and infleunce. From the creed of a small minority it became, within a century, the predominant and established religion of the largest empire on earth. Clearly, Constanstine was one of the great pivotal figures of European history. He has been ranked higher than better known figures such as Alexander the Great, Napoleon, and Hitler beecause of the enduring infleunce of his policies.