The site’s religious significance dates back to Adomnán, the ninth abbot of Iona who died in 704 and penned the famous biography of his kinsman St Colmcille. By the 12th century, Raphoe had been elevated to a diocesan see, marking its importance in the ecclesiastical hierarchy of medieval Ireland. The monastery once boasted a round tower, that quintessential symbol of early Irish Christianity, though Bishop John Leslie demolished it in 1636-7 to make way for his palace, which now occupies the tower’s former site.

The cathedral’s most intriguing survivors from the monastic period are two sections of a carved door lintel, likely dating from the ninth or tenth century. The left half, preserved in the cathedral vestibule, depicts the arrest of Christ with remarkable detail; St Peter cuts off the ear of Malchus, the High Priest’s servant, whilst a kneeling soldier with a lance appears in the corner, possibly representing Longinus. The right half, now weathered and set into the external north wall, shows fragments of the crucifixion scene with traces of winged figures and soldiers. These sculptural remnants offer a rare glimpse into the artistic sophistication of early medieval Irish stone carving.

The present cathedral building reveals a complex architectural biography spanning seven centuries. Thirteenth century sedilia and a piscina bowl in the chancel wall, discovered during restoration work around 1888, represent the earliest surviving fabric. The church underwent significant modifications in the 15th and 16th centuries, evidenced by cusped ogee windows and elaborate hood moulds, including one stolen terminal that depicted a dramatic hunting scene with a stag, attacking dog, and dragon. Bishop Andrew Knox repaired the “ruinated and all decayed” structure around 1622, whilst later bishops added transepts and a tower in the early 18th century. After decades of neglect that saw it dubbed “the most neglected church in the diocese” in 1876, architect Thomas Drew undertook a Victorian restoration around 1892, removing the transepts and creating the neo medieval chancel arrangement visitors see today.