St Oengus was a monk, bishop and reformer of the monastic life. He founded two ‘deserts’ for monks, one in Co Limerick, the other near Clonenagh in Co Laois. He wrote the famous ‘Felire Oengusso’ (Martyrology of Oengusso’) and perhaps the ‘Martyrology of Tallaght’ which may in origin go back to Lindisfarne.
St Oengus was the hermit whose love of solitude and prayer earned him the epithet ‘Culdee’ i.e. ‘servant of God’. This movement is not much understood but it affected many monasteries such as Armagh, Clonmacnoise, Devenish, Clones and Scattery Island; it was also strong in Scotland.