A viewer informed me: "In Church history we know at least three Saint Euthymios-es (IV/V - IX - Xth cent.)"
With his long beard this man is similar to the one I found as "The Great" in Wikipedia: (377-473), often styled the Great, was an Abbot in Palestine. Venerated in both Roman Catholic and Eastern Orthodox Churches. He was born in Melitene in Lesser Armenia. Christian tradition states that his parents had prayed for a son at the church of Saint Polyeuctus in Melitene.
He was educated by Bishop Otreius of Melitene, who afterwards ordained him priest and placed him in charge of all the monasteries in the Diocese of Melitene. At about thirty years of age he secretly set out on a pilgrimage to Jerusalem and remained for some time in a cave near a settlement of monks at a laura called Pharan, about six miles east of Jerusalem.
In 411 he withdrew, with St. Theoctistus, a fellow-hermit, into the wilderness, living in a rough cavern on the banks of a torrent. When many disciples gathered around them they turned the cavern into a church and built a monastery which was placed in the charge of St. Theoctistus. Euthymius, despite retaining his solitary lifestyle, gave direction for the others.
A miraculous cure which Euthymius was believed to have effected for Terebon, the son of the Saracen chief Aspebetus, spread the fame of the holy hermit far beyond the confines of Palestine. Aspebetus was afterwards ordained priest and became bishop over his tribe, in which capacity he attended the Council of Ephesus in 431.
When the report of this miracle had made the name of Euthymius famous throughout Palestine, and large crowds came to visit him in his solitude, he retreated with his disciple Domitian to the wilderness of Ruba, near the Dead Sea, living for some time on a remote mountain called Marda, whence he afterwards withdrew to the desert of Zipho (the ancient Engaddi).
When large crowds followed him to this place also, he returned to the neighbourhood of the monastery of Theoctistus, where he took up his abode in a cavern. Every Sunday he came to the monastery to take part in the Divine services. At length, because numerous disciples desired him as their spiritual guide, he founded in 420, on the right side of the road from Jerusalem to Jericho, a laura similar to that of Pharan. The church connected with this laura was dedicated in 428 by Juvenal, the first Patriarch of Jerusalem.
When the Fourth Ścumenical Synod (451) condemned the errors of Eutyches and Dioscorus, it was greatly due to the authority of Euthymius that most of the Eastern recluses accepted its decrees. The empress Eudoxia was converted to Catholic unity through his efforts."