Home» Monastic Sites» Derry» Tamlaght O’Crilly Monastery Tamlaght O’Crilly Monastery Derry erenaghs until early 17th century About This Site early monastic site; erenaghs until early 17th century Historical Information Alternative Names: Ta, lachta-mac-ninaich Other Sites in Derry Aghadowey Monastery early monastic site; hospital of St Gowry 1603 Learn More Aghanloo Monastery early monastic site; under erenaghs until 16th century Learn More Agivey Monastery early monastic site; purportedly founded 7th century by St Guar of Aghadowey; Cistercian monks grange of Macosquin Learn More Ballymagrorty Monastery (Derry Diocese) early monastic site, founded 6th century by St Colmcille Learn More