Here he was surprised at night by Hugh Dubh and Manus O'Donnell, and routed with the loss of goo men and an immense quantity of booty.
In the south Tighvein (1497 ft.) and Cnoc Dubh (1385 ft.) are the most important.
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.
A family quarrel ensued, and when Hugh Dubh appealed for aid against his son to the Maguires, Manus made an alliance with the O'Neills, by whose assistance he established his hold over Tyrconnel.
Hugh Dubh had been chief of the O'Donnells during one of the bitterest and most protracted of the feuds between his clan and the O'Neills, which in 1491 led to a war lasting more than ten years.
To a still elder branch belonged Daniel O'Donnell (1666-1735), a general of the famous Irish brigade in the French service, whose father, Turlough, was a son of Hugh Dubh O'Donnell, elder brother of Manus, son of an earlier Hugh Dubh mentioned above.