No likeness on file
John, son of Marcellinus and Mannea
martyr at Constanța in Scythia
SaintFull write-upDate unknown
Feast: 27 August (not on the universal Roman calendar; kept in the Roman Martyrology or local calendars)
Born
—
unknown
Died
—
unknown
Beatified
—
not on record
Canonised
—
not on record
Who they were
At Constanța in Scythia, in present-day Romania, the holy martyrs Marcellinus, a tribune, and Mannea, husband and wife, and John, their son, Serapion, a cleric, and Peter, a soldier.
The miracles
There was never a formal cause: he has been honoured as a saint since before the Church's formal processes began.
Why that counted as sanctity
The Roman Martyrology remembers him on 27 August as the son of the martyrs Marcellinus and Mannea, martyred at Constanța in Scythia, in present-day Romania.
Sources
Checked against the sources listed on 22 September 2026. Corrections welcome.