[1] The MacDonnells of Antrim were a sept of the powerful Clan Donald of the royal Clann Somhairle, (see Lords of the Isles), that the English crown had attempted to cultivate since the early 14th century in its efforts to influence the course of politics in Scotland.
The precise circumstances of this transfer or encroachment have been lost to history, but the English authorities, themselves preparing to claim overlordship in Ulster and the rest of Ireland, still recognised the Bissetts as the lords of the Glynns as late as 1515.
Once the invasion crisis had passed, the MacDonnells resisted efforts by the English and Scots governments to drive them from their lands in the Western Isles of Scotland and Ulster in Ireland.
Sorley Boy was born at Dunanynie Castle near Ballycastle, County Antrim in Ireland, and came to prominence during the mid-to-late 16th century, when the Dublin administration waged periodic campaigns in the Route.
This clan was the immediate rival of the MacDonnells in Ireland, dominating the northern portion of Antrim – the Route – with their stronghold at Dunluce Castle, near the mouth of the River Bush.
In 1558, the MacDonnell chieftain committed to him the lordship of the Route upon the death of his brother Colla, and Sorley Boy promptly raised a force of troops on the Scottish coast to confront the MacQuillans, former allies of the MacDonell clan.
Upon Elizabeth's accession in 1559 Sorley Boy had submitted to her authority under Thomas Radclyffe, 3rd Earl of Sussex, then Lord-Lieutenant of Ireland, and in return was confirmed in his Irish possessions.
Sussex retired in frustration, and O'Neill entered into a sustained offensive against the MacDonnells, ostensibly in the interests of ridding the English of Scottish interference in Ireland: he defeated Sorley Boy near Coleraine in the summer of 1564, laying waste his territory; in 1565 he invaded the Glynns, destroying all Scottish settlements there, and at the Battle of Glentasie he won a decisive victory, in which James MacDonnell and Sorley Boy were taken prisoner and Dunluce Castle fell into O'Neill's hands.
After his unexpected defeat by the O'Donnells in the battle of Farsetmore, O'Neill turned to the MacDonnells for assistance and attended a feast laid on by them at Cushendun, bringing with him out of captivity Sorley Boy and his late brother's widow, Agnes, to secure an alliance with the Scots.
Sorley Boy spent the next few years striving to frustrate the schemes of Sir Thomas Smith, and later of the Earl of Essex, for colonising Ulster with English settlers.
Essex then switched tack, having struck a deal with Turlough Lynagh, and defeated Sorley Boy around Castle Toome, where the Bann flows out of Lough Neagh.
Sorley Boy retaliated with a successful raid on Carrickfergus, in which the garrison broke before a highland charge, and managed to partly re-establish his power in the Glynns and the Route.
In alliance with Sir Hugh MacPhelim Bacagh O'Neill of Edenduffcarrick (Shane's Castle, Randalstown) and accompanied by two companies of English musketeers 'sent from the pale' and commanded by the newly appointed Senechel of Clandeboye, Captain Chatterton, the Mac Quillans launched a devastating raid on the northern glens.
[5] On surveying the results, Lord Deputy Sidney agreed to a ceasefire, although he supported the claims of the MacQuillans to the Route, and of Sorley Boy's nephews (sons of the widow Agnes) to possession of the Glens – a typical Campbell manoeuvre, effected through their alliance with Turlough Lynagh.
Most honorable Governor, it is and maybe truly said that there is no unhappiness comparable to his that may say he hath been once in good Estate, and is fallen from it through his own folly ; amongst many others in that case, I may and do reckon myself for none of the least, for being a man born out of this realm, and gotten large possessions in the same, whereupon I lived, though I might claim none by inheritance, I have very inconsiderately presumed to think I might as well hold it as I got it, by strong hand : carried on with this imagination, as one ignorant of Her Majesty's might and force, (and withal ill persuaded by others) I unhappily refused to come in to your Lordship, as the rest of Ulster did, now almost two years past, thinking it might suffice for me upon you- Lordship's repair into those parts to write a letter of some kind of observance unto you, with an offer after a sort to come myself.
And I do most faithfully promise to depend for ever upon Her Majestv's gracious goodness, according to such conditions as it shall please your most honourable Lordship to afford me on the behalf of Her Highness, whom I pray God long- to preserve.
During the previous forty years, he had played those difficulties with courage, skill and deception, to the point that MacDonnell's claims were largely accepted and the clan's fortunes secured.