Unfortunately, all was not so smooth; there was considerable sentiment against the change of law and authority involved in the change to an Earldom, and when Shane O'Neill, known as "Shane the Proud", Conn's legitimate son, grew up, he led a rebellion from 1551 onward, against Conn and Matthew and Anglo-Irish law.
When Brien was assassinated in 1562 by Turlough Luineach O'Neill, tanist to Shane the Proud, "between Carlingford and the Newry,"[2] his younger brother Hugh continued to be treated as Baron Dungannon; when he grew up, he fought alongside the Queen's government against his uncle Shane and his cousin Turlough.
This specificity was in part due to Earl Hugh's own marital complications; his first marriage, to his distant cousin, a daughter of Brien MacFelim O'Neill of Clandeboye, had been found invalid, and their children illegitimate; Hugh was the eldest son of his second wife, Joan O'Donnell, half-sister of the first Earl of Tyrconnell.
In 1608, King James I had attainted Hugh and his family, which deprived them of their lands and titles; the Irish Parliament confirmed this in 1614.
[3] The following men were called Baron of Dungannon: The title has also been extinct since the end of the male line of the grantee.