Constantine http://www.flickr.com/photos/spotsgot/3362379/In 305, illness prompted Diocletian's sudden abdication, thereby triggering a civil war from which Emperor Constantine I emerged victorious. He declared himself a Christian in 312, and in 313 he issued the Edict of Milan, which established equality among all religions. This legalized Christian worship for the first time. In 324, Constantine defeated the last of his opponents and became sole ruler of the Roman Empire.

Constantine hoped that Christianity would cement the stability of the empire, so one of his first actions was to encourage the Church to end doctrinal debates, and clearly articulate Christian belief and identity. Doctrinal debates surrounded the incarnation, with contradictory interpretations and beliefs about the true nature of Jesus—human and/or divine—and his relationship with God. Questions had arisen about which Gospels and letters should be read in Church. There was even contention about how disputes should be resolved.

In 325, Constantine convened the First Ecumenical Council at Nicaea in Asia Minor, the first council to include bishops from both the eastern and western regions of the empire. The Council issued a creed that affirmed the doctrine of the Trinity. The Nicene Creed, which summarizes the core of Christian belief, is seen as authoritative by all main branches of Christianity.

Nicene Creed
We believe in one God,

the Father, the Almighty,

maker of heaven and earth,

of all that is seen and unseen.

We believe in one Lord, Jesus Christ,

the only Son of God,

eternally begotten of the Father,

God from God, Light from Light,

true God from true God,

begotten, not made, one
     in Being with the Father.

Through him all things were made.

For us and for our salvation

he came down from heaven:

by the power of the Holy Spirit

he was born of the Virgin Mary,
     and became man.
For our sake he was crucified
     under Pontius Pilate,

he suffered, died, and was buried.

On the third day he rose again

in fulfillment of the Scriptures;

he ascended into heaven

and is seated at the right hand of the Father.

He will come again in glory to judge the living and the dead,

and his kingdom will have no end.

We believe in the Holy Spirit,
     the Lord, the giver of life,

who proceeds from the Father [and the Son].

With the Father and the Son he is
     worshiped and glorified.

He has spoken through the Prophets.

We believe in one holy catholic
     and apostolic Church.

We acknowledge one
     baptism for the forgiveness of sins.

We look for the resurrection of the dead

and the life of the world to come. Amen.

Constantine moved the capital of the empire from Rome to Byzantium (modern-day Istanbul) in 330. He consecrated the town to Christ and renamed it Constantinople. Indirectly and unintentionally, this set the stage for a series of events that would ultimately lead to a split between the eastern and western churches. While the split was not complete until the 11th century, the two sides of "Christendom," East and West, began to develop along parallel paths.

Spread of Christianity to AD 325 Spread of Christianity to AD 600 Source: Public Domain

In 381, Emperor Theodosius I made Christianity the official religion of the Roman Empire. Christian communities could be found as far west as the British Isles, south into north Africa and Ethiopia, north to the Danube and into modern-day Romania, and east from modern-day Turkey into Armenia and perhaps even India. Although the disintegration of the western Roman Empire was only decades away, the Christian churches in the east and the west quickly assimilated the Empire's structures of organization and authority and experienced a period of profound growth and change.

Study Questions:
1.     How did an understanding of idolatry affect early Christianity?
2.     Why were Christians persecuted in the early 2nd and 3rd centuries?
3.     Who was Constantine? How did he pave the way for the acceptance of Christianity?
4.     Describe the role of politics in the success of Christianity.

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