EMPEROR CONSTANTINE 306-337  

Roman devoted to Apollo, Sun God 
Conversion during war with rival Emperor Maxentius

312 BATTLE OF MILVIAN BRIDGE

           Sees cross inscribed on sun; hears voice
           "In hoc signo vinces. In this sign you shall win."

313 EDICT OF MILAN:
           freedom of worship for all religions, Christians

324 conquest of Eastern Empire
330 capital moved to Byzantium, renamed Constantinople
            Constantinople as 'new Rome,' 'capital of Christianity'
       remains capital until 1453 (captured by Ottoman Turks)

DONATION OF CONSTANTINE:

letter of Constantine to Pope Silvester I, dated 315:

    Imperial power in Rome & Western Empire
                  granted to Pope as Bishop of Rome;
    official basis for claims of secular power by Pope
               right to depose Emperors, Kings

    probably 8th C forgery (around 750) to explain
                    expansion of Papal States in central Italy