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Leo IV
pope of the Catholic Church
SaintResearchedBenedictinesDate unknown
Feast: 17 July (not on the universal Roman calendar; kept in the Roman Martyrology or local calendars)
Born
790
Died
17 July 855
verified
Beatified
—
not on record
Canonised
—
not on record
Who they were
Leo, a Roman educated at the monastery of St Martin, was unanimously elected pope in 847 after a Saracen raid on Rome.
Against his will made pope, he rebuilt the city walls and first enclosed the Vatican hill, creating the 'Leonine City'. He died in 855 and was buried in St Peter's; his biographer credits him with miracles.
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
A pope who protected Rome and St Peter's from invasion.
Sources
- Catholic Encyclopedia (1913), via New Advent - Pope St. Leo IV
- Wikidata Q228205 — dates, feast day and identifiers (CC0)
- English Wikipedia — Pope Leo IV (CC BY-SA)
Checked against the sources listed on 21 September 2026. Corrections welcome.