Arius was a Christian priest and theologian from the early 4th century, known for his teachings that sparked significant theological debates. He is best known for promoting the belief that Jesus Christ was not co-eternal with God the Father, suggesting that there was a time when Christ did not exist. This view led to the development of Arianism, a doctrine that was ultimately deemed heretical by the early Christian church. The controversy surrounding Arius's teachings culminated in the First Council of Nicaea in 325 AD, where church leaders convened to address the dispute. The council produced the Nicene Creed, affirming the belief in the co-eternity of the Father and the Son, which directly opposed Arius's views. His ideas, however, continued to influence various theological discussions for centuries.