Róis was one of some thirteen children of King of Ireland, Ruaidrí Ua Conchobair. About 1180 she married Hugh de Lacy, Lord of Meath (before 1179 to 1186).[3][4] This marriage angered King Henry II of England, as it had been undertaken without his permission.[4] Henry II may have feared that De Lacy was gaining too much power, and might, with this marriage, be planning to succeed Ruaidrí Ua Conchobair as king of Ireland.[1] To curtail this possibility, Henry II recalled De Lacy to England, twice, in 1179 and 1181.[2]
De Lacy had five daughters and two sons by his first wife Rose de Monmouth. Róis Ní Chonchobair was the mother of two more children, William Gorm de Lacy and Ysota de Lacy.[3][5][6][7]