O'Donnell, Caffar (d. 1608), prominent member of O'Donnell family, was the son of Aodh mac Maghnusa O'Donnell (qv) (d. 1600), lord of Tír Chonaill from 1566 to 1592, and his wife, Fiona MacDonnell (qv) (Iníon Dubh). He was a younger full brother to both Red Hugh O'Donnell (qv), the leader of the O'Donnells during the Nine Years War, and Ruaidhrí O'Donnell (qv), 1st earl of Tyrconnell. During the war he loyally supported Red Hugh. In 1599 he fought alongside his brothers at the O'Donnell victory over Sir Conyers Clifford's (qv) army in the Curlew Mountains. He also accompanied them on the march to Kinsale in the winter of 1601 and then fought in the battle on the losing Irish side. Following the battle he returned to Lower Connacht with Ruaidhrí and remained loyal to his family for the remainder of the war.
After the end of the war Caffar O'Donnell supported Ruaidhrí when he was made earl of Tyrconnell by King James I. He held lands at Ballindrait and married Rosa O'Doherty (qv), sister to the lord of Inishowen, with whom he had a son, Hugh, born in 1605. He also had by another woman an illegitimate son, Conn, who ‘was born with six toes upon one foot’. Sir John Davies (qv) stated in 1608 that O'Donnell's family held high hopes for this boy, ‘for they affirm that one of their saints of Tír Chonaill hath prophesied that when such a one, being of the sept of O'Donnell, shall be born, he shall drive all the Englishmen out of Ireland’ (Sir John Davies to Salisbury, 12 Sept. 1607, CSPI 1606–08, 270–71).
O'Donnell and his wife and son Hugh left Ireland with Ruaidhrí O'Donnell and Hugh O'Neill (qv) in the flight of the earls in September 1607. He also attempted to seize Conn from his foster-father, but the man made off with the child and O'Donnell had to leave Ireland without him. He took Hugh with him to Rome, but his wife remained in Flanders. Once in Rome he made the mistake of visiting the town of Ostia, ‘one of the worst and most unhealthy for climate in all Italy’, with his brother Ruaidhrí and Hugh, the son of Hugh O'Neill. He fell ill with a fever a day after Ruaidhrí, who died on 27 July 1608. Caffar remained seriously ill for two months and eventually died on 15 September 1608. He was buried in the church of San Pietro in Montorio alongside his brother. The Irish annals record that he was remembered for the feasts he gave to entertain his followers. His widow remained unmarried for a number of years but eventually became the wife of Owen Roe O'Neill (qv). Caffar and Rosa's son Hugh was killed in 1625, while Conn was brought up in the household of the lord deputy of Ireland, Viscount Falkland (qv). Later he was imprisoned in London. In 1629 he escaped to Flanders with his cousins Mary Stuart O'Donnell (qv) and Hugh O'Rourke.
Caffar's cousin, Caffar Óg O'Donnell (d. 1609), was the son of Caffar O'Donnell (d. 1580), a tánaiste of Tír Chonaill, and the grandson of Manus O'Donnell (qv), lord of Tír Chonaill from 1537 to 1555. Caffar O'Donnell built Scarriffhollis Castle on an important ford on the River Swilly, near Letterkenny; this fortress, together with three quarters of land, passed to Caffar Óg on the death of his father. Caffar Óg was a first cousin of Red Hugh O'Donnell and had ambitions to succeed him as lord. In 1602 and 1603 he marched into Boylagh in western Tír Chonaill to oppose another rival relative, Niall Garvach O'Donnell (qv), and his English allies. However, on the latter occasion he was captured by Niall. He was imprisoned by the English until 1609, when he was ‘attainted of high treason’ and ‘put to death at Dublin . . . on the 18th of July’ (Inquis. Rot., ii, appendix V, Donegal, p. 7; AFM, 1609). The Annals of the Four Masters state that ‘It would have been no disgrace to the tribe of Conall, son of Niall, to elect this good man as their chief’. It is not known if Caffar Óg ever married or had any children. His second cousin Shane MacManus Óg O'Donnell (d. c.1608) was the son of Manus Óg O'Donnell, a prominent noble who was killed by some of the O'Gallaghers in 1586, a grandson of the chieftain Manus O'Donnell, and a first cousin of Red Hugh O'Donnell. He too desired to become lord of Tír Chonaill, and on 3 August 1608 the lord deputy of Ireland, Sir Arthur Chichester (qv), stated to the lords of the privy council that he was ‘ambitious to be created O'Donnell after the manner of the country’ (SP 63/224). Shane first came to prominence in 1589 when he killed Manus O'Donnell, a brother of Niall Garvach. He had lands and ‘a strong fort’ at Dunboy on the shores of Lough Swilly as well as a strongly fortified castle on the east of Tory Island, and made his living from fishing.
As the Nine Years War progressed Shane O'Donnell decided to oppose Red Hugh. In April 1598 he made a secret agreement with Sir Conyers Clifford, but when he returned to Tír Chonaill on Clifford's instructions Red Hugh had him arrested. He played little part in the remainder of the war but in 1608 he used the outbreak of the O'Doherty rebellion as an opportunity to become lord of Tír Chonaill. Having gathered a small following, he was besieged in Tory Castle by Sir Henry Folliott. Folliott captured his son, aged ten, and his daughter, aged eleven (he had married a sister of Brian Óg O'Rourke (qv), the lord of Breifne), but Shane himself managed to escape to Arran Island. Although he intended to flee to Connacht, he disappears from all records and may have drowned.