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Theodor von Sitten
Swiss Christian bishop
SaintResearchedAncient RomePre-congregation
Feast: 16 August (not on the universal Roman calendar; kept in the Roman Martyrology or local calendars)
Born
400
Died
400
Beatified
—
not needed: before formal processes
Canonised
By tradition
recognised before formal processes began
Who they were
At Sion in the Valais in present-day Switzerland, Saint Theodor, first bishop of the city, who, following the example of Saint Ambrose, defended the Catholic faith against Arianism and venerated with every honour the relics of the martyrs of Agaunum.
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 16 August as the first bishop of Sion, who defended the faith against Arianism.
Connected on this site
- Ulrich of Augsburg Saint“There are also accounts of his relics being moved to Bischofszell and by Ulrich of Augsburg to Ottobeuren.” — Wikipedia
Sources
- Roman Martyrology, 16 August (Italian Bishops' Conference, Santo del giorno)
- Wikidata Q332831 — dates, feast day and identifiers (CC0)
- English Wikipedia — Theodore of Octodurum (CC BY-SA)
Checked against the sources listed on 22 September 2026. Corrections welcome.