Saint Constantine was a Roman Emperor from 306 to 337 AD of Thracian-Illyrian ancestry. Constantine was the son of Flavius Valerius Constantius, a Roman army officer, and his consort Helena. His father became Caesar, the deputy emperor in the west in 293 AD. Constantine was sent east, where he rose through the ranks to become a military tribune under the emperors Diocletian and Galerius. In 305, Constantius was raised to the rank of Augustus, senior western emperor, and Constantine was recalled west to campaign under his father in Britannia. Acclaimed as emperor by the army at Eboracum (Modern-day York) after his father's death in 306 AD, Constantine emerged victorious in a series of civil wars against the emperors Maxentius and Licinius to become sole ruler of both west and east by 324 AD. As emperor, Constantine enacted many administrative, financial, social, and military reforms to strengthen the empire. The government was restructured and civil and military authority separated. A new gold coin, the solidus, was introduced to combat inflation. It would become the standard for Byzantine and European currencies for more than a thousand years. The first Roman emperor to claim conversion to Christianity, Constantine played an influential role in the proclamation of the Edict of Milan in 313, which decreed tolerance for Christianity in the empire. He called the First Council of Nicaea in 325, at which the Nicene Creed was professed by Christians. In military matters, the Roman army was reorganised to consist of mobile field units and garrison soldiers capable of countering internal threats and barbarian invasions. Constantine pursued successful campaigns against the tribes on the Roman frontiersthe Franks, the Alamanni, the Goths, and the Sarmatianseven resettling territories abandoned by his predecessors during the turmoil of the previous century. The age of Constantine marked a distinct epoch in the history of the Roman Empire. He built a new imperial residence at Byzantium and renamed the city Constantinople after himself (the laudatory epithet of "New Rome" came later, and was never an official title). It would later become the capital of the Empire for over one thousand years; for which reason the later Eastern Empire would come to be known as the Byzantine Empire. His more immediate political legacy was that, in leaving the empire to his sons, he replaced Diocletian's tetrarchy with the principle of dynastic succession. His reputation flourished during the lifetime of his children and centuries after his reign. The medieval church upheld him as a paragon of virtue while secular rulers invoked him as a prototype, a point of reference, and the symbol of imperial legitimacy and identity. Beginning with the Renaissance, there were more critical appraisals of his reign due to the rediscovery of anti-Constantinian sources. Critics portrayed him as a tyrant. Trends in modern and recent scholarship attempted to balance the extremes of previous scholarship. Constantineas the first Christian emperoris a significant figure in the history of Christianity. The Church of the Holy Sepulchre, built on his orders at the purported site of Jesus' tomb in Jerusalem, became the holiest place in Christendom. The Papal claim to temporal power was based on the supposed Donation of Constantine. He is venerated as a saint by Eastern Orthodox Christians, Byzantine Catholics, and Anglicans.