CIRCUMINCESSION (circuminsessio, circum-inessio). - A term of Greek derivation, used to denote the mutual immanence of the three Persons of the Holy Trinity, each of whom dwells in the other two, according to the formula of the Council of Florence, taken from St. Fulgentius (De fide ad Petrum, cap. 1, n. 4: PL 65, 674): «The Father is entirely in the Son, entirely in the Holy Spirit; the Son is entirely in the Father, entirely in the Holy Spirit; the Holy Spirit is entirely in the Father, entirely in the Son» (Denz-U, 704). This truth, explicitly revealed in Holy Scripture (Jn 10:38; 14:11; 17:21; 1 Cor 2:10-11), is universally attested by tradition, is based on the numerical unity of the divine essence, and presupposes the real distinction of the Persons among themselves, as well as a certain vital cycle, which implies the vital origin of one Person from another and the vital return of the proceeding Person to its principle. Thus the Son proceeds from the Father, returns to the Father, and dwells in the bosom of the Father. The Holy Spirit proceeds from the Father and the Son, to whom He returns and in whom He dwells.
This latter dynamic aspect of circuminsession is more clearly expressed by the Greek term περίχώρησις (περι-χώσέω = to go around) and by the Latin circumincessio (circum-incedere = to move around), while circuminsessio emphasizes the static aspect of the same truth (circum-in-sedere = to sit in, to sit around). Περίχώρησις is first used by St. Gregory Nazianzen (Ep., 101: PG 37, 182), but only to denote the mutual penetration of the two natures in Christ. As a Trinitarian term περίχώρησις does not appear before St. John Damascene (De fide orthodox., I, 8, 14: PG 94, 829). Its Latin translation, circumincessio, due to Burgundio of Pisa (d. 1194), is not used by Peter Lombard or St. Thomas, but occurs frequently in the works of St. Bonaventure and other Franciscan authors. Later this term was replaced by circuminsessio, which first appears in Henry of Ghent (d. 1293), after which it is used universally even outside the Franciscan school. Circuminsession sums up the entire Trinitarian doctrine and constitutes the briefest refutation of all errors concerning this mystery.