England made Conn O'Neill's son by a blacksmith's wife his heir, and Conn's son Shane had the heir killed

Gaelic Irish lordships passed by tanistry: the successor was chosen from male kin descended from a common great-grandfather, the eldest and most worthy, not the eldest son. Under Henry VIII's policy of surrender and regrant, Conn Bacach O'Neill gave up his Gaelic title and in 1542 was made Earl of Tyrone under English law. The patent named as his heir Matthew, made baron of Dungannon. Matthew was born in Dundalk to Alison Kelly, a blacksmith's wife, and was presented to Conn at about 16, who accepted him as his son. Conn's son Shane disputed this. He said Matthew was the blacksmith Kelly's son, and he had the larger following. Shane's men killed Matthew in 1558. Shane was inaugurated as The O'Neill under Gaelic custom. In 1562 he went to London, and Elizabeth I let him return recognized as The O'Neill but never made him earl. The O'Donnells defeated him at Farsetmore, and in 1567 the MacDonnells, from whom he sought help, killed him at Cushendun and sent his head to Dublin Castle. Matthew's son Hugh became the 3rd Earl of Tyrone. A court decision under James I abolished tanistry and imposed English land law.