The apostles who walked with Jesus during his ministry, and led the Church in the first decades of the Christian era, knew Jesus as Messiah, the anointed of God. He was “the Christ, the Son of the living God” (Matthew 16:16). He had
existed from the beginning of God’s creation. Later he was made flesh, born a human being, walked among men, taught his disciples, and gave his life a ransom for all (John 1:14, 1 John 1:1-3, Matthew 9:6, 20:28).
However, as the apostles passed away, confusion entered respecting the nature of Jesus. His followers debated who he was and his relationship to the Heavenly Father. Perhaps this was because there never was another person like Jesus,
and he sometimes spoke cryptically about who he was. Remarkably, the matter is murky in the minds of many Christian even today.
HISTORICAL SETTING: THE ROMAN EMPIRE
In 325 AD, the Roman Emperor Constantine called a great church council to debate and decide the matter. Why would
Constantine do this? Why did he care whether there was agreement about who Christ is and his relationship to
God, our Heavenly Father?
Read more here: The Real Story Behind the Council of Nicaea