nendrum abbey and monastic site

Nendrum owes its origin to St Mochaoi who died before 500, and who is said to have been converted to Christianity by St. Patrick. It may not have developed into a monastery until the 7th century, when its island location made it easily accessible by sea, though this later proved a disadvantage when it probably fell a prey to the Vikings.
The location of the ancient monastery was rediscovered by Bishop Reeves in 1844, and Lawlor's extensive, if inadequately recorded, archaeological explorations in the years 1922-24 make it probably the most extensively excavated early Irish monastery. Three concentric walls divide the area of the old monastery into separate precincts of ever increasing size, of which the smallest contained the monastery buildings proper - a small stone church (with restored west wall and lintelled door) and the stump of a Round Tower, both probably built in the 10th or 11th century, though the eastern extension of the church may have been built by the Benedictines who settled here under John de Courcy in the late 12th century.