The Nine Years War was the greatest challenge that Gaelic Ireland presented to the Elizabethan English state. The role played by the young chieftain, Red Hugh O'Donnell (1572-1602), in the Gaelic confederacy that fought this war, was crucial. Without him, the possibility of such successful and wide-ranging resistance to the expansion of English power in Ireland would not have possible. This book represents a major reappraisal of O'Donnell's role. It is a study of how the abuse of power by English captains and officials led to the growth of anti-English sentiment in the lordship of Tír Chonaill and in O'Donnell's thinking itself, due in large part to his imprisonment in Dublin Castle. It is also a study in how the Gaelic lordships of Ulster proved themselves to be capable of military and political innovation, to enable their leaders to fashion a formidable confederacy which came very close to ending English sovereignty over Ireland.