GREGORIANA, ACQUA. — It is prepared with salt, ash, and wine and is used in the consecration of a church for exorcistic purposes. St. Gregory the Great mentions it (Epist., 11, 56), indicating its use for the purification of pagan temples in England, and the rite is attributed to him; but it was probably already in use beforehand (cf. Optatus, De schismate Donatist., 66, 6; Pope Vigilius, Epist. ad Profuturum, 4).
References to a mixture of wine and water appear in the Sacramentarium Franco-rum, while a mixture of salt and ash, along with many exorcistic formulas derived from the Gallican rite, is found in the Gregorian Sacramentary of the 9th–10th century. The current blessing formula contains the Ordo ad aquam benedictam faciendam, the prayer Sancti-ficare, which is also found in Ambrosian and Visigothic ritual books, and a praise of water taken from a homily by St. Ambrose (Expositio Evang. sec. Lucam, 10, 48). The *a. g.* is used with a sprig of hyssop, since this plant was also anciently regarded as a means of purification (cf. Lev. 14, 4–49, 52; Num. 19, 6–17; 9; Ps. 50, 8).