The territory of the Route was originally part of Twescard,[3] a county of the Earldom of Ulster that at its height stretched from the Glens of Antrim to Inishowen.
By the 1460s, the de Mandevilles, who held manors in Twescard, decided to abandon them and sold their land to the MacQuillans,[3] who according to the Annals of Ulster were already in the region warring with the O'Cahans as far back as 1442.
[3] Both families had previously held the office of "constable of the bonnaght" for the Earldom of Ulster - a system adopted from the Irish where mercenaries were hired to act as a body of standing troops.
[4] Sir John Perrot, Lord Deputy of Ireland, successfully reduced parts of Ulster into allegiance to the English during the reign of Queen Elizabeth I.
A month beforehand, Sorley Boy's nephew had received a grant in similar terms of the greater part of 'the Glynns' (the Glens of Antrim).
Seeing an opportunity to expand his territory and influence, Sorley Boy MacDonnell, with the aid of levies from Scotland, launched a mass assault on the Route against the McQuillans.