Since the 1660s, the incorruptible relics of the Patriarch of Constantinople Athanasius III (Patellarius), buried according to a Greek custom in a seated position, have been venerated in the Mgar Holy Transfiguration Monastery near the town of Lubny in the Poltava province of the historical Malorussian region. Due to the prolonged uncertainty concerning the official recognition of him as a saint, the iconography of the patriarch is virtually devoid of traditional iconographic images. Instead, small pilgrimage depictions of the shrine with his relics or the entire tomb complex have become widespread. The icons and iconographic samples found in museums and private collections, as well as documents on the transfer of the relics and the design of the reliquary, allow us to expand our understanding of the specifics and stages of development of this peculiar composition. The article brings to light several successive iconographic renditions, associated with the manufacture of a new reliquary and the saint’s increased veneration after the publication of hagiographic materials. While the majority of the surviving icons were made in the modern-day territories of Ukraine, they were in demand and copied by the masters of central Russia. The portrayals of Saint Athanasius III, created in the monastery workshops or commissioned by the Mgar monastery, characterize the little-known center of local icon painting of the late 18th – mid-19th centuries.