Flavius Valerius Constantinus, the son of Saint Helena, was proclaimed Roman Emperor at York in AD 306. He was the first Emperor to support the Christians and during his time of stable government, not only did the persecutions cease but he actively supported the growth of Christianity. In AD 311, the Edict of Toleration ended the persecutions started under Emperor *Diocletian and in AD 313, the Edict of Milan restored the property of the churches. Constantine not only ensured that churches and monasteries could now legally hold property but he also provided for grants to be made available for churches and supported church building and restoration programmes from public funds. The Caesareum at Alexandria (where the cult of the Roman Emperors had been celebrated) was now dedicated as a church to St. Michael, and it later became the official seat of the Patriarch of Alexandria. Constantine held a series of Councils to attempt to unite the various factions in the Church, the most notable being the Council of Nicaea.
In Egypt, the government was reorganised, the country was made into a diocese and divided into six provinces. Constantine founded Constantinople in AD 324-30, and it was inaugurated as a city in AD 330. It was the first Christian city and, as an imperial capital, was intended to act as an eastern counterbalance to Rome; its significance to Egypt was that it lessened Alexandria's influence in the East and also became the recipient, instead of Rome, of much of Egypt's grain surplus.
Christianity developed and spread in Egypt both during and after Constantine's reign; in the Temple of Luxor, originally dedicated to the Egyptian gods Amun, Mut and Khonsu, there remains an altar dedicated to Constantine.
BIBL. Jones, A.H.M. Constantine and the conversion of Europe. London: 1972; Baynes, N. H. Constantine the Great and the Christian Church. London: 1972.
Biographical Dictionary of Ancient Egypt by Rosalie and Antony E. David
Ancient Egypt. A Reference Guide. EdwART. 2011.