The Constantinian Dynasty refers to a series of Roman emperors who ruled from the early 4th century to the early 5th century AD. It began with Constantine the Great, who reigned from 306 to 337 AD and is known for establishing Constantinople as the new capital of the Roman Empire. This dynasty is significant for its role in the transition of the Roman Empire from paganism to Christianity. Following Constantine, his sons and relatives continued to rule, including Constantius II and Constans. The dynasty is marked by internal conflicts and power struggles, as well as the establishment of the Nicene Creed during the First Council of Nicaea in 325 AD, which aimed to unify Christian doctrine.