The Roman Emperor Constantine -- C. Flavius Valerius Constantinus -- was born at Naissus, Serbia, between 274 and 288 and died May 22, 337, at Nicomedia. (You can put those date in context by looking at the major events timeline.) Upon the death of his father, Constantius Chlorus, on 25 July, A.D. 306, Constantine was proclaimed Caesar by his troops. Constantine wasn't the only claimant. When he fought against rival emperor Maxentius at the Milvian Bridge, he had a vision that let him know that he could win the battle, but only under the sign of Christ. Wearing a sign of Christ, Constantine won. Constantine, whose mother (St. Helena) may have already been Christian, may have resisted converting to Christianity until he was on his deathbed, at which time he was finally baptized, by the Arian Bishop Eusebius. Whatever his personal beliefs, Constantine made Christianity legal throughout the Empire, in 313, by means of the Edict of Milan. He also presided at the religious Council of Nicea, which settled Christian doctrine for the ages.
Examples: The dynasty of Constantine included Constantine I, Licinius, Maximinus IIm Valerius Valens, Martinian, Constantine II, Constans, Constantius, Julian, and Jovian. Constantine's dynasty was followed by the dynasty of Valentinian.