St. Constantine the Great and the Christiqan church and Jerusalem

Emperor Constantine I (AD 306-37)
Originally uploaded by Nickmard

Saint Constantine (/'kɒnstɛntaɪn/), was Roman Emperor from 306, and the undisputed holder of that office from 324 until his death in 337.

Best known for being the first Christian Roman Emperor, Constantine reversed the persecutions of his predecessor, Diocletian, and issued (with his co-emperor Licinius) the Edict of Milan in 313, which proclaimed religious toleration throughout the empire, says Wikipedia.

His mother was St Helena, a convert to Christianity who built the Church of the Holy Sepulchre over the site of Jesus' crucifixion and burial.

Constantine left Rome and ruled the empire from the city of Byzantium, a metropolis he renamed Constantinople.