d. 1492 (traditional; some scholars propose c. 1430–1473)
After a vision of an icon of the Dormition, he founded a monastery on the Yakhrom River and served as its abbot, reposing in 1492.
Our Venerable Father Cosmas of Yakhrom
Cosmas of Yakhrom was a fifteenth-century Russian monastic who, after experiencing a vision and discovering a miraculous icon of the Dormition of the Mother of God on the Yakhrom (Yakhroma) River, founded the Holy Dormition Monastery there and served as its first abbot (igumen).
By tradition he was born into a noble boyar family in the region between Vladimir and Yuryev-Polsky, in what is now Vladimir Oblast; his birth name, date, and birthplace are not recorded. He entered service with an aristocratic household and received an education considered excellent for the era.
He is venerated in the Russian Orthodox Church as a Venerable (preподобный) monastic, commemorated on February 18 (the day of his repose) and October 14, the latter associated with the Yakhrom Icon of the Dormition.
According to his life, while still in the service of a boyar, Cosmas accompanied his ailing master on a journey seeking medical treatment along the Yakhroma River. There he experienced a vision of extraordinary light and discovered an icon of the Dormition of the Mother of God affixed to a tree.
He presented the icon to his sick master, who was healed upon contact with it. Cosmas received a divine command to become a monk and to build a monastery.
After his term of service ended, Cosmas traveled to the Kiev Caves Lavra (Kievo-Pecherska Lavra), where he was tonsured a monk and distinguished himself through ascetic practices that impressed even experienced monks. The life relates that he later received angelic instruction to leave the Lavra and retrieve the Dormition icon.
Returning to the place on the Yakhrom River where the icon had appeared, Cosmas built, with donations from pious benefactors, a church dedicated to the Dormition of the Mother of God, roughly forty versts from Vladimir. By tradition this foundation, the Holy Dormition Monastery of Yakhrom, was established around 1482–1483. A community of monks gathered around him and he became its igumen (abbot). His ascetic reputation is said to have reached the Great Prince.
The official record holds that Cosmas reposed on February 18, 1492, and was buried in the monastery he had founded; one account places his death at Nebyloye, in the present-day Yuryev-Polsky District.
Scholars dispute this date: some sources propose he died between 1464 and 1473, and others as early as around 1430. He was canonized as a Venerable in the Russian Orthodox Church.
Cosmas's relics rest beneath the Dormition cathedral of the monastery he founded. Tradition records miraculous healings attributed to veneration at his tomb.