23rd January, (10th January O.S.):
- AGATHO, (On Eastern Calendars 20th February), Pope of Rome from A.D. 678 until his repose in A.D. 681. Originally from Palermo in Sicily, he called for the holding of the Sixth Œcumenical Council in Constantinople in A.D. 680 against Monothelitism.
- DERMOT (DIARMIS, DIARMAID), (sixth century), Known from his earliest years for his sanctity, he was the spiritual father and teacher of St. Kieran of Clonmacnoise (9th September). St. Dermot went on to found, and serve as first abbot of a monastery on Innis-Clotran Island (Inchcleraun), Co. Longford Ireland.
- JOHN CAMILLUS THE GOOD, a Bishop of Milan who worked against Arianism and Monothelitism, and reposed circa A.D. 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 A.D. 987.
- PETRONIUS, born in Avignon, he became a monk at Lérins and served as Bishop of Die from circa A.D. 456 until his repose circa A.D. 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 A.D. 660.
- THOMIAN (TOIMEN), St. Thomian was the seventeenth Archbishop of Armagh, from circa A.D. 623 until circa A.D. 660. Always renowned for his great sanctity of life, he is also remembered for a letter he wrote to Rome concerning the Paschal Controversy.
* - 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."