Kosmas 16 was hegoumenos of the monastery of Hagios Petros of Ydendra; in 787 he attended the Second Council of Nikaia (the Seventh Ecumenical Council) and is attested at the fourth session, on 1 October 787, when he subscribed the statements read out from the Fathers in support of the veneration of icons: Mansi XIII 156 (Κώνστας ἡγούμενος τοῦ ἁγίου Πέτρου Υδενδρων (no breathing or accent on the last word); the Latin version, at XIII 155, styles him "Constantinus hegumenus sancti Petri Hydendrensium"; marginal notes in Mansi give his name as Kosmas, Κοσμᾶς is recorded as v. 1. Confusion is easy between Κοσμᾶς and Κῶνστας, a frequent abbreviation for Konstantinos). He probably attended other sessions of the Council also; see Gregorios 45.

(Publishable link for this person: )