Peraeans

Peraeans were the followers of Euphrates of Pera, in Cicilia, who is said to have believed that there are in the Trinity three Fathers, three Sons, and three Holy Ghosts. It has been alleged that in opposition to this class of heretics was framed the clause in the Athanasian creed which says, "So there is one Father, not three Fathers; one Son, not three Sons; one Holy Ghost, not three Holy Ghosts."

⇒See also the International Standard Bible Encyclopedia.