After Shane's murder Turlough was next in line as his Tainaiste. Sydney had some trouble in negotiating with turlough; and White, the master of the rolls. writes that he "has taken Harry, the son of Shane, O'Neill out of Dublin Castle to practice some conclusion...by show of Harry to the Irish.Turlough was in very bad health at this time and there was talk of nominating his successor. In 1579 Sir Edward Fytton states that there were four competitors for the title of O'Neill, namely Hugh, the Baron of Dungannon, and Shane's son, Shane Óg, who were the strongest; and Turlough Brasselagh, grandson of Con Baccagh, and Art, son of Henry ( of the fews ), who were the weakest.In the August time, at the head of 5,000 men, Turlough advanced on the pale, to demonstrate in favour of the rebel Lord Baltinglass. Turlough declared, writes Lord Gonnanston, that he is, and will be O'Neill" and will stand in defense of religon while life doth last. Turlough was in alliance with the Scottish monarch, afterwards James the first of England; James had sent him " great gifts, with 400 of his guardsmen.With these troops, and 4,700 horse and foot of his own, he invaded O'Donnell and" slew many of his chief captains and many of his men. A truce was arranged, to settle the controversies between them. Turlough entered Breffny and obliged O'Rielly to deliver up Con, son of Shane O'neill, who, in a foray, was taken prisoner.Shane Og, Conn's brother, refusing to surrender to O'Rielly on this occasion, was slain. In May Turlough again sickened, and lay unconscious for two days, when it was reported that he was dead; and Shane O'Neill's sons, who the English called, the most venomous persons in the state, have combined with the Scots to put Hugh, the baron of Dungannon, from succession.Shane's sons were the popular candidates for the chieftainship; but against the Baron and the English they had little chance; so like the popular candidates in Clannaboy, they got nothing but hard knocks, spending most of their time in the dungeons of Dublin Castle, Dungannon, or Strabane; for they were much feared by Turlough as they were hated by the Hugh O'Neill and the English.Hugh obtained from the Queen possession of the Blackwater fort, to lie with his forces in case of Turlough's death. From this on Hugh the Baron of Dungannon had it all his own way, being supported by the enemies of the O'Neill, in and out of Ulster.Turlough illness encouraged O'Donnell to invade Tyrone. On his recovery Turlough endeavoured to stir up rebellion in Munster and Connaught which ended in failure. For the next few years there was wheeling and dealing, threats skirmishes death, alliances made and broke, in May 1593, Turlough resigned due to ill health, the Chieftainship to his rival Hugh O'Neill, namely the Earl, and Turlough made peace with Hugh and O'Donnell. Turlough, who the Annalists remark, was "a Lord bountiful in peace and powerful in war, until age and infirmity overcame him," passed away in Strabane in 1595 and was ininterred in the Church of Ardstraw.