his marriage to Isabel de Clare, daughter of Strongbow and Aoife Mac Murchada, daughter of Diarmait Mac Murchada. Marshal began stone construction on the large fortification at Kilkenny Castle which was completed by 1195 and was largely responsible for forcing the Mac Giolla Phádraigs from their southern power base around the River Nore; their ancient rights revoked and a decree of expulsion pronounced on the entire clan. The northern districts of Mag Lacha and Ui Foircheallain (henceforth called Upper Ossory) which had formerly broken away from Osraige under Ua Caellaighe/Ua Faeláin and Ua Dubhsláine rule since 1103, and which had subsequently seen English settlement from the Normans, thus became targeted by the expelled Mac Giolla Phádraigs and their Ossorian followers for resettlement. This caused a land war in Upper Ossory between those clans already residing there, the new English settlers, and the incoming clans from south and central Osraige driven out by Earl Marshal, which lasted more than a century and a half before the Mac Giolla Phádraigs established full supremacy over the region. Subsequently, the chaos of this poorly recorded conflict caused the then bishop of Ossory, Felix Ua Duib Sláin, to permanently remove the episcopal see from Aghaboe and initiate construction of the cathedral in Kilkenny. Upper Ossory thus remained an independent Gaelic lordship until the mid-sixteenth century, with its Mac Giolla Phádraig rulers retaining claims to the kingship of all Osraige and being recorded as such, or sometimes "King of the Slieve Blooms". The majority of Osriage was divided up and partitioned amongst various Norman adventurers, especially those within the household of William Marshal who arrived to take charge of lands which were claimed by his wife's inheritance. Likely arriving under Marshal was Sir Thomas FitzAnthony who was granted extensive lands in lower Ossory and elsewhere (Thomastown, Co. Kilkenny is named after him) and was an important and successful administrator for the Crown; being made seneschal of all Leinster from 1215 to at least 1223. Upper Ossory was formally incorporated into the Henry VIII's Lordship of Ireland by the submission of Barnaby Fitzpatrick, 1st Baron Upper Ossory under the policy of surrender and regrant in 1537. This ironically had the effect of preserving Gaelic culture in Upper Ossory long into the future, since the Crown no longer dealt harshly with the territory. In 1541, The Mac Giolla Phádraig was ennobled as Baron Upper Ossory. Other members of