Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity.[h] He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire. He founded the city of Constantinople (now Istanbul) and made it the capital of the Empire, which it remained for over a millennium.
 
The age of Constantine marked a distinct epoch in the history of the Roman Empire and a pivotal moment in the evolution from classical antiquity to the Middle Ages. He built a new imperial residence in the city of Byzantium, which was officially renamed New Rome, while also taking on the name Constantinople in his honour. It subsequently served as the capital of the empire for more than a thousand years—with the Eastern Roman Empire for most of that period commonly referred to retrospectively as the Byzantine Empire in English. In leaving the empire to his sons and other members of the Constantinian dynasty, Constantine's immediate political legacy was the replacement of Diocletian's Tetrarchy with the principle of dynastic succession. His memory was held in high regard during the lifetime of his children and for centuries after his reign. The medieval church held him up as a paragon of virtue, while secular rulers invoked him as a symbol of imperial legitimacy. The rediscovery of anti-Constantinian sources in the early Renaissance engendered more critical appraisals of his reign, with modern and contemporary scholarship often seeking to balance the extremes of earlier accounts.
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