Spyridon (Greek Spyridōn) was — per the foundational Cypriot tradition preserved by his contemporary biographer Theodore of Paphos — a Cypriot peasant shepherd. He married, fathered a daughter (Irene), and was widowed. After his wife's death he was elected by acclamation Bishop of the small Cypriot diocese of Trimythous, where he continued — even as bishop — to pasture his sheep and work his fields.
Spyridon was one of the 318 bishops at the Council of Nicaea in 325 (his name appears on the surviving Cypriot delegation list). According to the celebrated medieval tradition, during the council's debates over the Trinitarian doctrine — when the philosophical-theological arguments had reached an impasse — Spyridon, the unlettered peasant-bishop, took a clay brick in his hand and said: 'There is in this brick the elements of fire, water, and earth — three substances yet one brick' (or, in another version, 'Just as fire rises from this brick, water flows from it, and earth remains — so are the three Persons one God'). At the moment he spoke, the brick suddenly burst into fire in his hand, water dripped from it, and clay-dust fell to the ground — the foundational early-Christian theological argumentum-by-miracle, preserved across the entire Byzantine and Coptic traditions.
He governed his small Cypriot see for 25 years and died on December 12, 348. His incorrupt body remains the principal sacred relic of the island of Corfu — translated from Cyprus in the 7th century during the Arab conquests, then translated again to Corfu in 1456 by a Cypriot priest fleeing the Ottoman conquest of Constantinople. The reliquary is processed through Corfu town four times each year, and Corfiote tradition continuously maintains that the velvet slippers of the body (changed each year) show signs of wear — that Spyridon walks the streets of Corfu at night to visit the sick and the poor.