What was the importance of the nicene creed?

The Nicene Creed is a "symbol" of Christian belief in all regions and all denominations.

It ultimately explains the Church's teachings about the Trinity and also affirms the historical realities of the life of Jesus Christ. It is based on biblical concepts and truths though it does not directly quote the Scripture.

The Ancient Nicene Creed was accepted by the Catholics, Orthodox, and many Protestants. The Creed was written in AD 325, defined by Church Bishops at the Councils of Nicaea, and was completed in its present form in AD 381, added on by Constantinople.