When Finn Mac Cumhall dwelt in Ireland, there lived an ancient family of distinction in Knocknagoshel. This family was of the O Reilly clan and it consisted of Mr and Mrs O Reilly and two boys named Shawn and Fergus. Mr O Reilly was married secondly and thus Shawn had a stepmother who treated him most unkindly.
Fergus and Shawn resembled each other so much that Mrs O Reilly consulted a witch as to how she might discern them. The witch gave her a means of knowing her son and she cut Shawn's golden hair so that she might discern the boys asunder. Shawn being twenty one years left home as he was very angry with his stepmother