[[Image:Nicaea icon.jpg|right|thumb|An icon depicting the First Council of Nicaea]]
In the mid-first century, Christianity spread beyond its Jewish origins under the leadership of the Apostles, especially [[Saint Peter|Peter]] and Paul of Tarsus. Within a generation an episcopal hierarchy can be seen, and this would form the structure of the Church.<ref>Catholic Encyclopedia, [http://www.newadvent.org/fathers/3801.htm ''Canons of the Council of Nicaea''], especially canon 6.</ref>Christianity spread east to Asia and throughout the Roman Empire, despite Persecution of Christians by the Roman Emperors until its Edict of Milan by Constantine I (emperor) in 313. During his reign, questions of orthodoxy lead to the convocation of the first Ecumenical Council, that of First Council of Nicaea.
In 391 Theodosius I established Nicene Christianity as the official and, except for [[Judaism]], only legal religion in the Roman Empire. Later, as the political structure of the empire collapsed in the West, the Church assumed political and cultural roles previously held by the Roman aristocracy. Eremitic and Coenobitic monasticism developed, originating with the hermit Anthony the Great around 300. With the avowed purpose of fleeing the world and its evils ''in contemptu mundi'', the institution of monasticism would become a central part of the medieval world.<ref>Jo Ann H. Moran Cruze and Richard Gerberding, ''Medieval Worlds'' pp. 118-119</ref>