MANUS O'DONNELL (d. 1564), son of Hugh Dubh O'Donnell, was left to rule Tyrconnel during his father's pilgrimage to Rome about 1511; and retained the chief authority when Hugh Dubh returned. A family quarrel ensued, but with the help of the O'Neills, Manus established his hold over Tyrconnel. In 1522, however, the O'Neills and O'Donnells were again at war. Conn Bacach O'Neill, 1st earl of Tyrone, determined to subjugate the O'Donnells. Supported by several septs of Munster and Con naught, and assisted by English contingents and the MacDonnells of Antrim, O'Neill took the castle of Ballyshannon, and after devastating a large part of Tyrconnel encamped at Knockavoe, near Strabane. Here he was surprised at night by Hugh Dubh and Manus O'Donnell, and severely defeated. The war continued, however, and in 1531 O'Donnell applied to the English Govern ment for protection, giving assurances of allegiance to Henry VIII. In 1537 Lord Thomas Fitzgerald and his five uncles were exe cuted for rebellion in Munster, and the English Government made every effort to lay hands also on Gerald, the youthful heir to the earldom of Kildare, a boy of 12 years of age who was in the secret custody of his aunt Lady Eleanor McCarthy. This lady, in order to secure a powerful protector for the boy, accepted an offer of marriage by Manus O'Donnell, who on the death of Hugh Dubh in July 1537 was inaugurated The O'Donnell. Conn O'Neill was a relative of Gerald Fitzgerald, and this event accordingly led to the formation of the Geraldine League, a federation which combined the O'Neills, the O'Donnells, the O'Briens of Thomond, and other powerful clans; the primary object of which was to restore Gerald to the earldom of Kildare, but which afterwards aimed at the complete overthrow of English rule in Ireland. In
Aug. 1539 Manus O'Donnell and Conn O'Neill were heavily de feated by the lord deputy at Lake Bellahoe, in Monaghan.
In the west Manus continued to assert the supremacy of the O'Donnells in north Connaught, where he compelled O'Conor Sligo to acknowledge his overlordship in 1539. In 1542 he went to England and presented himself, together with Conn O'Neill and other Irish chiefs, before Henry VIII. In his later years Manus was harassed by his son Calvagh, who imprisoned him in 1555, and deposed him from all authority in Tyrconnel. He died in 1564. Manus O'Donnell is also described by the Four Masters as "a learned man, skilled in many arts, gifted with a profound intellect, and the knowledge of every science." At his castle of Portnatrynod near Strabane he supervised if he did not actually dictate the writing of the Life of Saint Columbkille in Irish, which is preserved in the Bodleian library at Oxford. Manus was sev eral times married. His first wife, Joan O'Reilly, was the mother of Calvagh, and two daughters, both of whom married O'Neills; the younger, Margaret, was wife of the famous rebel Shane O'Neill. His second wife, Hugh's mother, by whom he was an cestor of the earls of Tyrconnel (see below), was Judith, sister of Conn Bacach O'Neill, 1st earl of Tyrone, and aunt of Shane O'Neill. He died in