23rd January, (10th January O.S.):
- AGATHO, (On Eastern Calendars 20th February), Pope of Rome from 678 until his repose in 681. Originally from Plarmo in Sicily, he called for the holding of the Sixth Œcumenical Council in Constantinople in 680 against Monothelitism.
- DERMOT (DIARMIS, DIARMAID), sixth century — the spiritual father of St. Kieran (9th September) of Clonmacnois, and later founder of a monastery on Innis-Clotran Island in Ireland.
- JOHN CAMILLUS THE GOOD, a bishop of Milan who worked against Arianism and Monothelitism, and reposed circa 660.
- PETER URSEOLUS, a Venititan who served as Admiral of the Venetian fleet and then Doge of Venice. After two years as Doge he abondoned the world to become a monk at the monastery of Cuxa, where he later lived as a hermit until his repose in 987.
- PETRONIUS, born in Avignon, he became a monk at Lérins and served as Bishop of Die from circa 456 until his repose circa 463.
- SETHRID (SAETHRYTH), a stepdaughter of Anna, King of East Anglia, and half-sister of Ss. Etheldred (Audrey) (23rd June) and Ethelburgh (7th July). She became a nun at Faremoutiers-en-Brie under St. Fara (3rd April), whom she succeeded as abbess. St. Sethrid reposed circa 660.
- THOMIAN (TOIMEN), an archbishop of Armagh in Ireland from 623 until his repose circa 660.
* - Prior to the Schism the Patriarchate of Rome was Orthodox and fully in communion with the Orthodox Church. As Saint John of Shanghai and San Francisco +1966 said "The West was Orthodox for a thousand years, and her venerable Liturgy is far older than any of her heresies."