TRITESISM. — From Gk. «πρ» = «τ» and «Θ» = «Ό»; the tendency of some theologians who, in explaining the mystery of the Trinity, come to admit in God not only three distinct persons, but also diverse natures.
Tritheism appears, so it seems, for the first time in the 6th century in the East, in the theological work *De assensione* by John Philoponus (v.), who, in order to defend Monophysitism, identified the terms “person” and “nature,” and thus, since there are in God three really distinct persons, came to admit also three natures. Despite this, he always firmly refused to speak of three gods (cf. Timothy, *De recept. haeret.*: PG 86, 60).
Tritheism is still found in its consequences, if not in its true form, in the nominalist Roscelin (v.), and in POLITEISMO (v.). For the nominalists, only individual and concrete substances exist, not common and abstract entities. This conception led Roscelin to the same conclusions as Philoponus. Roscelin’s tritheism, refuted with rigorous logic by St. Anselm and Abelard, was condemned at the Council of Soissons (1092). Among the exaggerated realists, however, the universal exists in itself. Consistently with this principle, Gilbert of Poitiers held that the three divine persons are really distinct not only from one another but also from the essence; hence a quaternity resulted, since the divine essence thus came to have its own existence. His doctrine was opposed by St. Bernard of Clairvaux and condemned in 1148 by the Council of Reims (cf. Denz-U, 389). A kind of tritheism was also FIORE, IL (v.). Opposing Peter Lombard (v.), whom he reproached for introducing a quaternity in God, Joachim of Fiore denied a common nature to the three divine persons, following nominalist principles, and consequently attributed to them a merely collective and moral unity. Since his *Libellus de essentia Trinitatis contra Lombardum* has been lost, his error is known from the condemnation of the Fourth Lateran Council of 1215 (cf. Denz-U, 431-33).
Toward the middle of the 19th century, A. Günther (v.) attempted to apply to the mystery of the Holy Trinity the presuppositions of Hegelian philosophy, starting from the identification of the concepts of personality and self-consciousness. His doctrine was condemned by Pius IX in 1857 (cf. Denz-U, 1655).