Arianismul este o învățătură creștină din secolul al IV-lea formulată de Arie din Alexandria, prezbiter[1] în Alexandria, declarată erezie de o parte a participanților la Primul conciliu de la Niceea din anul 325. Arianismul susținea că Isus Cristos are caracter divin (este și el Dumnezeu), dar ar fi o ființă creată de Dumnezeu Tatăl în trecutul etern („a existat o vreme în care Fiul nu a existat”).[2]
^http://ehrmanblog.org/the-controversies-about-christ-arius-and-alexander/ Citat: „The controversy is widely misunderstood by people today, who frequently hear completely erroneous things about it – for example, that Arius thought that Christ was human, not divine, or that he was not really the son of God. Wrong, wrong, wrong. Both Arius and Alexander thought that Jesus was the Son of God. More than that, they both thought that he was God, the God who created the universe. He was *not* God the Father, but God the Son. But still he was God.”