The flight of James II after the Battle of the Boyne rendered Dublin an open city. Tyrconnell and other Jacobite commanders understood that the city could not be defended. The capital was strategically vulnerable and there was the additional tactical problem of the large number of Protestant refugees from elsewhere in Ireland sheltering in the city. Defending Dublin from William's advancing forces and securing the city from civil unrest within its limits would have been extremely tricky at best and, even had time permitted, would have required denuding the rest of Ireland of Jacobite troops; Tyrconnell and his allies within James's cabinet now had no choice but to agree with the original advice of English and French strategists to withdraw beyond the Shannon. Frustrated by James's behaviour, Tyrconnell and his advisors lost interest in supporting the monarch's broader goals and devised a rear-guard campaign designed to secure the west and to await French support.

In Dublin, William's supporters moved quickly once they recognized that defeat at the Boyne had led to a more comprehensive Jacobite retrenchment. But the defeat of James and the possibility of a comprehensive Williamite victory in Ireland was not a source of unalloyed joy for Church of Ireland adherents, especially those who remained in Ireland.

The armed resistance in Ireland to James had been mounted almost exclusively in a swathe of Ulster from Derry to Enniskillen and up to the northeast coast.