Fitzgerald, eighth earl of Kildare [q.v.], was born about 1484, and succeeded nis elder brother, Art Oge O'Neill, as chief of Tyrone in 1519. His connection with the house of Kildare rendered him naturally hostile to Henry's policy of anglicising Ireland, and immediately on the arrival of the Earl of Surrey in 1520 he invaded the English Pale. His attempt to obstruct Surrey's government was not, however, very successful, owing to the hostility of Hugh 'Black' O'Donnell, and the support which the Earl of Ormonde rendered to the viceroy, and before long he submitted. In the hope of retaining him in his obedience, Henry sent him 'a collar of gold of our livery,' and authorised Surrey to make him a knight, and, if possible, to induce him to repair to England. In the foUowingyear he consented to accompany the viceroy against O'Melaghlin, but was compelled, much to Surrey's annoyance, to return to defend his own country against O'Donnell, with whom his strife was incessant. He retaliated in 1522 by invading Tyrconnel, and was successful in capturing Ballyshannon, Bundrowes, and Belleek; but in a pitched battle at Knockavoe, near Strabane, he was utterly defeated by O'Donnell. In 1524 Kildare succeeded Ormonde as viceroy , and at his installation O'Neill carried the sword of state before him. In 1528, during Kildare's detention in England, O'Neill and Brian O'Connor [q. v.] did their utmost, acting on Kildare's instructions, to obstruct the government of the Earl of Ormonde. Some stronger hand than Ormonde's was needed to suppress them, and in 1530 the deputyship was transferred to Sir William Skeffington [q. v.]
The restoration of Kildare, and his substitution for Skeffington in August 1532, established things on their old footing, and complaints were soon rife that O'Neill was allowed to plunder the Pale at his pleasure. He supported the rebellion of 'Silken Thomas,' but, after the capture of Maynooth, submitted to Skef&ngton at Drogheda on 26 July 1535. He renewed his submission to Lord Leonard Grey in the following year ; but the deputy, though he found him 'very tractable in word,' could not, without employing force, ' whereunto time serveth not,' persuade him to put in hostages for his loyalty. The result was that next year (1537) O'Neill attacked Ardglass. Orey wished to retaliate by invading Tyrone, but he was overruled by the council, and commissioners were sent to treat with O'Neill, who found him 'very reasonable,' but obstinate in his refusal to give hostages for his loyalty. He renewed his assurances of loyalty in the following year, but early in 1539 he concluded an alliance with Manus O'Donnell [q. v.] at Donegal, the object of which was supposed to be the restoration of Gerald Fitzgerald, the young heir to the earldom of Kildare. Failing to induce O'Neill to surrender Fitzgerald, Grey invaded Tyrone, and ravaged much of his country. O'Neill and O'Donnell in the autumn invaded the Pale with the greatest army, as some thought, that had ever been seen in Ireland. After burning Navan and Ardee,and accumulating immense booty, they were on their way homewards when they were overtaken and utterly defeated by 'Grey at Ballahoe. In May 1540 O'Neill consented to parley with the lord justice. Sir William Brereton, at the Narrow-water, and promised to obser'e the conditions of the treaty made with Skeffington in 1535. But his agents were at the time in Scotland negotiating for assistance, and there was a plot on foot to inveigle the lord justice to Fore in Westmeath, under pretence of parleying, preparatory to a general attack on the Pale.
The plot was frustrated by Brereton ; but the hollowness of O'Neill's professions was sufficiently apparent, and after vainly endeavouring 'by all honest persuasions to bring him to conformity,' St. Leger determined to prosecute him with fire and sword. He was fortunate to detach O'Donnell and some of his urraghs or vassal chiefs from him, and in September 1541 he invaded Tyrone. O'Neill made an unsuccessful counter-attack on the Pale, and the lord deputy, after destroying 'miche of his comis and butters, whiche is the grete lyvinges of the said Oneil and his followers,' retired. A few weeks later he again invaded Tyrone, and carried off several hundred head of cattle. A third invasion in December brought O'Neill to his knees. He sent letters to St. Leger at Armagh, offering unqualified submission, and promising, as no O'Neill had ever done before, to surrender his son as hostage for his loyalty. It was doubtful if his submission would be accepted, for the propriety of extirpating him and planting his country with English settlers had been seriously mooted. But the difficulties in the way of such a plan were insuperable, and St. Leger thougnt it wise to accept his offer, and ' to beate him, and siche like as he is, with the same rodde that they have often betenyour subjects here ; that is, to promyse theim faier, to wynne tyme, whereby other enterprises more benificiall for your poore subjectes here mought be acheved.' Accordingly O'Neill, having promised to become a loyal subject, to re-