Orthodox Saints of the Pre-Schism See of Rome
DEUSDEDIT of CANTERBURY, a native of Wessex (England), whose Saxon name was Frithona, and of whose early life nothing is known. St. Deusdedit succeeded St. Honorius of Canterbury (30th September) to the See of Canterbury in 655, becoming the first Anglo-Saxon to serve as Primate. The consecration of Damian as Bishop of Rochester in 656 is the sole official act of his that is known with absolute certainty. St. Deusdedit reposed a casualty of the Great Pestilence of 664.
FELIX of COMO, the first Bishop of Como (northern Italy), and a friend of St. Ambrose of Milan (7th December). St. Felix was an enthusiastic and energetic pastor. He reposed circa 390.
IDUS of LEINSTER, (Fifth Century), St. Idus was a disciple of St. Patrick of Ireland (17th March), who baptised him and later made St. Idus Bishop of Alt-Fadha, Leinster in Ireland.
JUSTUS of ROME, (Date Unknown), a soldier in the Roman Imperial Army, and a Christian. St. Justus is said to have been martyred in Rome.
LIBERT, a Flemish monk martyred by the Normans in 835.
MARCELLINUS (MARCHELM, MARCULF), an Englishman who went to Flanders (north-eastern France) to assist St. Willibrord of Echternach (7th November) in his mission. There, along with St. Lebuin of Deventer (12th November), he preached the Gospel to the people of Overijssel in present-day eastern Netherlands. St. Marcellinus reposed at Oldenzeel circa 762, and his relics were later translated to Deventer.
OPTATIAN of BRESCIA, a late fourth century Bishop of Brescia in Lombardy (northern Italy). St. Optatian reposed circa 505.
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”.
Details of British Saints excerpted from Orthodox Saints of the British Isles.
Details of continental saints from these sources.
In many cases there are several spelling versions of the names of saints from the British Isles. I use the Oxford Dictionary of National Biography version as the primary version with the more prevalent version in parenthesis e.g. Ceadda (Chad) of Lichfield.