"Saint Cosmas came from Bulgaria where his devout parents provided him with a good education in Slavonic and Greek. They wanted him to marry but he was drawn by the love of Christ and, unknown to them, made his way to the Holy Mountain of Athos to become a monk at the Bulgarian monastery of Zographou. On the feast of the Annunciation at the Monastery of Vatopedi, he saw a woman among those serving in the Church and in the refectory, and he was grieved at first to observe this breach of the monastic rule, but overjoyed when he realized that it was the Mother of God who had appeared to him in this way.

"He was clothed in the holy angelic Habit and, after some time, was ordained priest. One day, as he was praying before the icon of the Mother of God, asking her with tears how to achieve his salvation, he heard a voice saying, 'Let my servant withdraw to the desert outside the monastery.' He was obedient to the will of God and, with the blessing of his Abbot, lived in silence from then on. Some years later, he was found worthy of the grace of discernment of thoughts and of beholding things happening elsewhere, as well as of other spiritual gifts. In the course of many years, he was the spiritual helper of a great number of monks. At the end of his life, Christ appeared to him saying that he would shortly have a great trial to endure from the Devil. Indeed, the prince of demons made his appearance next day with a host of his servants bewailing and bemoaning their inability to annihilate their great enemy Cosmas, who had held them in check for so long and gained possession, by his virtue, of the throne in Heaven that had once been Lucifer's. Taking a heavy stick, the demon beat the Saint so violently that he left him half-dead. As God allowed, Saint Cosmas died in peace two days later, on 22 September 1323. When the fathers came from the monastery to bury him, the wild animals gathered round. They kept silent until the end of the service, but howled unusually loud as his body was covered with earth. Then having paid their respects, they made off into the wilderness. Forty days later, the monks came to take up the body of Saint Cosmas and translate it to the monastery, but it was no longer in the grave. Where it now is God alone knows." (Synaxarion)