The news of the flight of O’Neill and O’Donnell caused, throughout the greater part of Ulster, the utmost consternation. Abandoned like sheep without their shepherds, the clansmen of Tfr Owen and Tfrconnell knew not what fate might befall them. The English Government, fearing lest, in their despair, they might resort to desperate courses, endeavoured to allay their anxiety. A Proclamation was issued by the King, in which he declared that he would take into his own hands the possessions of the fugitive earls, and would protect the rights of all those who had held estates under them. At this very time a scheme for an extensive Plantation had been laid before James by Chichester.

In 1608, a singularly rash and ill-advised insurrection gave an excuse for extending still further the projected confiscations. Its leader was the young Sir Cahir O’Doherty, chief of Inishowen. He quarrelled on some private matter with Sir George Paulet, Governor of Derry, and, in the course of the dispute, Paulet struck him in the face. Vowing vengeance, Sir Cahir withdrew. Niall Garff was afterwards said to have encouraged the misguided youth to his ruin, and young O’Hanlon and some others certainly promised assistance.

By a dishonourable stratagem, he obtained possession of the fort of Culmore on the Bann, and marching thence, surprised Derry, where Paulet was slain. These successes were due, however, merely to the unprepared state of the garrisons, and when the Lord Deputy, apprised of what had occurred, sent to the north a force of three thousand men, O’Doherty was unable to make any stand against them. He himself was slain in a skirmish, and his head was set on a pole over one of the gates of Dublin. Niall Garff and Donall O’Cahain were arrested for their alleged share in the insurrection, and both ended their days as prisoners in the Tower.