The present Church of Ireland St Munchin's is located on King's Island, at a place overlooking the River Shannon, just within the ancient town wall. Perhaps because Mainchín's church had to contend with the rival interests of Mungret, a few miles south-west of the town, which was the head church of the powerful Uí Fhidgeinte, and had claims to episcopal status, it appears never to have attained importance. It is entirely ignored by the annalists. Moreover, neither Mainchín nor his church find mention in the ninth-century Tripartite Life of St Patrick (qv), which brought its subject to the area immediately about Limerick. The Norse settlement on King's Island may have contributed to this lack of interest in Mainchín's church. With the foundation of the cathedral church of St Mary's in the late twelfth century, Mainchín's church became a prebend. His feast-day is celebrated in Limerick on 2 January.