Joannes
Martyrological notice
The historical Roman Martyrology commemorates Joannes on 27 April. The Latin notice identifies the record as abbot. The source places the commemoration at Constantinopoli.
Historical martyrology witness · Martyrologium Romanum (Latin historical edition)
Constantinopoli sancti Joannis Abbatis, qui pro cultu sacrarum Imaginum, sub Leone Isaurico, plurimum decertavit.