text: The Edict of Serdica, also called Edict of Toleration by Emperor Galerius, was issued in 311 in Serdica (today Sofia, Bulgaria) by the Roman emperor Galerius, officially ending the Diocletianic persecution of Christianity in the East. In the 3rd century the number of Christians grew. When Emperor Constantine of Rome issued the Edict of Milan in 313, thus ending all Roman-sponsored persecution of Christianity, the area became a haven for Christians. Just twelve years later in 325, Constantine assembled the First Council of Nicaea. In 391, Theodosius I made Christianity the official religion of Rome.
  The East-West Schism, known also as the Great Schism (though this latter term sometimes refers to the later Western Schism), was the event that divided Christianity into Western Catholicism and Greek Eastern Orthodoxy, following the dividing line of the Empire in Western Latin-speaking and Eastern Greek-speaking parts. Though normally dated to 1054, when Pope Leo IX and Patriarch of Constantinople Michael I Cerularius excommunicated each other, the East-West Schism was actually the result of an extended period of estrangement between the two Churches.
  The primary claimed causes of the Schism were disputes over papal authority—the Pope claimed he held authority over the four Eastern patriarchs, while the patriarchs claimed that the Pope was merely a first among equals—and over the insertion of the filioque clause into the Nicene Creed. Most serious (and real) cause of course, was the competition for power between the old and the new capitals of the Roman Empire (Rome and Constantinople).
  There were other, less significant catalysts for the Schism, including variance over liturgical practices and conflicting claims of jurisdiction.
  Early Middle Ages