According to tradition, St. Patrick himself founded this monastery, which occupies prime land sloping gently towards Lough Foyle to the east. The site’s importance was further revealed in 2014 when the Bernician Studies Group conducted a magnetometer survey in the surrounding fields, uncovering the outline of the Early Christian monastery’s ecclesiastical enclosure beneath the earth.

A routine clean-up of the graveyard in 2010 led to an unexpected discovery of several previously unrecorded cross-slabs hidden amongst the weathered stones. The Bernician Studies Group’s subsequent survey documented twenty cross-slabs within the graveyard, including ten distinctive ringed cross-inscribed examples. Among these finds, one particularly intriguing piece consists of the lower half of a cross-slab, decorated with an incised shaft ending in a pointed terminal. This fragment has been rather unceremoniously inserted sideways into the graveyard surface, just east of the standing southern wall section of the medieval church ruins.

These cross-slabs serve as tangible links to Cooly’s monastic past, each one a testament to the craftspeople who carved them and the community they served. The variety of designs, from simple crosses to more elaborate ringed versions, suggests a long tradition of stone carving at the site, possibly spanning several centuries of the monastery’s active life. The sideways placement of the fragmentary slab raises questions about later reorganisation of the graveyard, perhaps during periods when the original significance of these markers had been forgotten or when practical concerns took precedence over preservation.