 The earliest associations of the Uí Ceinnselaig are with the region around Rathvilly, County Carlow, and the headwaters of the River Slaney, but in time the centre of their power was pushed southwards, later being found around Ferns, County Wexford, site of the monastery of the saint Máedóc of Ferns (d. 626 or 632).In early times the kings of Leinster came from the Uí Ceinnselaig and the Uí Dúnlainge, but the Uí Dúnlainge came to dominate the kingship of the province, and after Áed mac Colggen (d. 738) it was three hundred years until the next Uí Ceinnselaig king of Leinster, Diarmait mac Máel na mBó ("see" list of Kings of Uí Cheinnselaig).A branch of the family, the descendants of the Uí Ceinnselaig dynast Murchad mac Diarmata meic Máel na mBó, took the surname "mac Murchada" (from which modern Irish "Mac Murchadha", anglicised as "MacMurrough", "Murphy", "Morrow", etc.