PLACIDUS, saint. — Disciple of St Benedict. The only biographical source concerning him is the Dialogues of St Gregory the Great (II, 3-7; PL 66, 140-46; critical ed. by U. Moricca, Rome 1924, pp. 85-90), from which we learn that at the age of seven P. was offered to St Benedict at Subiaco by his father Tertullus, a Roman patrician; having fallen into the Nero lake while fetching water, he was miraculously brought ashore by St Maurus (v.).
His cult has undergone an evolution, on which U. Berlière has shed light (v. BIBLICA). The earliest documents commemorate him on 5 Oct as a “confessor.” In the second half of the 11th century, the opinion began to circulate at Monte Cassino that the Sicilian martyr of the same name (v. following entry), commemorated on the same day in the Hieronymian Martyrology, might be the disciple of St Benedict; this hypothesis was embellished by the librarian and archivist Peter the Deacon (d. c. 1159) in his Life (or Acts) of SS Placidus and his brothers Eutychius, Victorinus and their sister Flavia etc., which he attributes to Gordian, a supposed companion of the saint who escaped the pirate massacre at Messina (text in Mabillon, Acta SS. Ord. Benedict., I, Paris 1668, pp. 45-79; and in Acta SS. Octobris, III, Antwerp 1770, pp. 114-38). Thus the mission of P. in Sicily to found monasteries (like that of St Maurus in Gaul) and his martyrdom belong to legend, which nevertheless entered, in the 16th century (v. following entry), into the Roman Breviary and Martyrology (5 Oct).