Mac Giolla Phádraigs or Fitzpatricks of Ossory are probably matrilineal descendants of the Uí Ímair. King Cerball was an ally of their (probable) founder Ívar the Boneless, the Viking king of Waterford. It is also possible that Donnchad's father, Gilla Pátraic mac Donnchada, was somehow a relation of Ívar the Boneless, who had a son named Gilla Pátraic. Derbforgaill ingen Tadhg Mac Giolla Pádraig (Princess of Osraige, died 1098) Derbforgaill, daughter of Tadhg Mac Giolla Pádraig was married to Toirdelbach Ua Briain, king of Munster and de facto high king of Ireland. From him, she bore two sons: Tadhg and Muirchertach Ua Briain, who also later became high king. She reposed in 1098 in Glendalough. Saints with Ossory connections The monastic settlements of Saighir, Aghaboe and Kilkenny were planted by Christian saints. The activity of Christian religious leaders under the patronage of the kings did much to increase the learning, literacy and culture within the kingdom. According to his vitae, Saint Patrick traversed Osraige on his route to Munster, preaching, converting, founding churches and leaving behind holy relics and a disciple named Martin. A number of other saints had connections to Ossory, working both within Ireland and abroad in Britain and Europe: St. Ciarán of Saighir "The Elder", himself a scion of the Ossorian ruling Dál Birn lineage is reputed to have evangelized the kingdom before the arrival of St Patrick who also preached there. He founded the church of Saighir from which he evangelized the kingdom. It eventually became the episcopal see of Ossory, and the burial place of its Christian kings. St Ciarán was succeeded by his disciple, St Carthage the Elder. St Ciarán's feastday is 5 March, along with St. Carthage and St. Piran. St. Kieran's College in Kilkenny (Ireland's oldest Roman Catholic secondary school) is named after him. (In Cornwall St. Ciarán is identified as one and the same person with Saint Piran, the patron saint of tin miners and all Cornwall.) A relief statue of St. Ciarán stands in a high niche atop the Chapter House at St. Mary's in Kilkenny. St. Carthage the Elder, a son or grandson of Óengus mac Nad Froích and St. Ciarán's successor at Saighir. His feastday is also celebrated with St. Ciarán on 5 March. St. Cainnech of Aghaboe established two monastic centers in Ossory in the 6th century, at Aghaboe and Kilkenny, now named after him. His feast