Arius (born around 260, died 336 in Constantinople) was an early Christian thinker. He lived in Alexandria, but was probably born in Libya. He did not agree with his bishop Alexander who said that Jesus and God were the same. Arius said Jesus and God were not the same since there was a time when Jesus did not exist.
At the First Council of Nicea, most bishops did not vote with Arius; the official document says that God the Father and Jesus the Son were of the same essence, and therefore the same being. They voted that Jesus and God had existed together for all time.