The O'Rourke family were recognized as one of the most illustrious of medieval Eire. Descent from the legendary Gaelic invaders, 'The Milesians' (The Milesian sailed from Galicia to Ireland.) Great Sean Ferghal O Ruairc. He was the first to use the name as part of a hereditary surname and the first of any king in the country to be called O Ruairc. He was born in Ireland at the start of the 10th century and became as king of Connacht one of the strongest tribal chiefs in western Ireland and also a prominent leader in the whole of the country. (Sean) Ferghal O Ruairc battled far outside his stronghold in Breifne. Around the time 952 – 954 he waged war on the territories of Cairbre and Teathbha which are south of Breifne. In 957 he led a raid on the North of Ireland and was victorious against the Cenel Eoghain of the northern Ui Neill clan. In 960 he was raiding the men of north Munster. (Sean) Ferghal's battles made the O Ruaircs the powerful family they would be known as.