Placidus
Christian monk and martyr
Feast: 5 October (1962 Missal) · not on the current Roman calendar
Who they were
Placidus, son of the patrician Tertullus, was brought as a child to St Benedict at Subiaco and offered to God. St Gregory the Great tells how, when he fell into the lake below the monastery, his fellow monk Maurus, sent by Benedict, ran across the water and drew him safely to shore. He almost certainly went with Benedict to Monte Cassino around 529.
Nothing is known of his later life. The account of his martyrdom, which claims to be by his servant Gordianus, is now held to be the work of Peter the Deacon, a twelfth-century monk of Monte Cassino, who seems to have confused him with an earlier Placitus martyred in Sicily under Diocletian with Euticius and thirty companions, whose feast fell on 5 October.
The miracles
There was never a formal cause: Placidus has been honoured as a saint since early times, listed among the confessors after Benedict and Maurus in ancient litanies. He is often called a martyr; the Catholic Encyclopedia judges that a later confusion.
Why that counted as sanctity
Placidus is honoured as one of St Benedict's first disciples, given to God as a child and formed by Benedict himself.
- Catholic Encyclopedia (1913), via New Advent - St. Placidus
- Wikidata Q3906150 — dates, feast day and identifiers (CC0)
- English Wikipedia — Placidus (martyr) (CC BY-SA)
Checked against the sources listed on 21 September 2026. Corrections welcome.