The Orthodox Christians that follow the Julian calendar observe the Day of Saints Emperor Constantine and his Mother Helena on June 3, Info-Prim Neo reports. Constantine the Great or Saint Constantine 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. Constantine experienced a dramatic event in 312 at the Battle of Milvian Bridge, after which Constantine would claim the emperorship in the West. It is said that Constantine looked up to the sun before the battle and saw a cross of light above it, and with it the Greek words "Εν Τουτω Νικα" ("by this, conquer!", often rendered in the Latin "in hoc signo vinces"). Constantine commanded his troops to adorn their shields with a Christian symbol (the Chi-Ro), and thereafter they were victorious. The Emperor also transformed the ancient Greek colony of Byzantium into a new imperial residence, Constantinople, which would remain the capital of the Byzantine Empire for over one thousand years. The Byzantine liturgical calendar, observed by the Eastern Orthodox Church, lists both Constantine and his mother Helena as saints. Constantine was baptized on his deathbed by Eusebius, bishop of Nicomedia, and died shortly afterward. He was buried in the Church of the Holy Apostles, his mausoleum. Helena discovered the True Cross on which the Lord was crucified on Golgotha. Initially, she found three different crosses. The True Cross was tested by its' causing a man to rise from the dead. She built Churches in Bethlehem, Egypt, the Mount of Olives, and Mount Calvary, and died in Palestine during these activities.