13th century (Constantine reposed ca. 1240)
Disciples in the tradition of Sts Barlaam of Khutyn and Anthony of Dymsk who founded a monastery on a wilderness peninsula at Kosinsk near Staraya Russa.
Our Venerable Fathers Constantine and Cosmas, Abbots of Kosinsk
Saints Constantine and Cosmas of Kosinsk were thirteenth-century monastic founders venerated together as the first abbots of the Kosinsky Saint Nicholas Monastery near Staraya Russa, in the Novgorod lands of medieval Rus'. They stood within the monastic tradition of Saint Barlaam of Khutyn and his successor Saint Anthony of Dymsk, as whose followers they were formed before withdrawing to found a community of their own.
About the year 1220 the two left the Khutyn monastery and settled on a wilderness peninsula roughly three versts from the city of Staraya Russa, on the land enclosed by the Rivers Polista and Smezhnya. There they established a monastery dedicated to Saint Nicholas, with Constantine serving as its abbot until his death around 1240. Cosmas continued the ascetic labors of his mentor and was laid to rest in the same grave; the two are commemorated as a single pair on July 29.
Constantine and Cosmas were monastic followers of Saint Barlaam of Khutyn (commemorated November 6) and of his successor Saint Anthony of Dymsk (commemorated January 17). This lineage placed them within one of the foundational currents of Novgorod monasticism, and it was from the Khutyn community that they departed to begin their own foundation.
Around 1220 the two settled upon a wilderness peninsula situated roughly three versts from the city of Staraya Russa, on the spit of land between the Rivers Polista and Smezhnya. There they founded a monastery in the name of Saint Nicholas, which Constantine headed as abbot until his death about the year 1240.
After Constantine's repose, Cosmas continued the ascetic exploits of his mentor and was in time buried in the same grave with him, the two founders sharing a single tomb as they had shared a single labor.
The relics of the two saints rest beneath the vestibule of the Nikolaev (Saint Nicholas) church, which was built in 1820 over the tomb of the founders at the site of their monastery near Staraya Russa.
Named pair commemorated as one.