(fôs´t s s s ´n s) (KEY) or Fausto Sozzini (fou´st s t-ts ´n ) (KEY) , 1539–1604, Italian religious reformer, founder of Socinianism. Socinus left the Roman Catholic Church when, influenced by the writings of his uncle, Laelius Socinus, he came to deny the Trinity and other traditional doctrines. Faustus left Italy for Basel in 1575, and in 1579 he went to Poland, where he spent the remainder of his life. In Poland he gradually organized the anti-Trinitarian groups into the sect of Polish Brethren and thereby founded the movement known as Socinianism.
