Above: Map of Leinster

In Leinster, meanwhile, another insurrection had broken out under the leadership of James Eustace, Viscount Baltinglass. Baltinglass had some personal grievances: he had been fined for attending Mass, and he alleged, besides, that he could not admit the title of the Queen to be regarded as Head of the church. Fiach Mac Hugh O’Byrne, the powerful Wicklow chief, joined him, and they lurked amongst the mountains, waiting for a favourable opportunity to attack the English forces. This opportunity was soon afforded them by the imprudence of the new Deputy. In spite of the advice of those of his officers who were experienced in Irish wars, he started out against the enemy, marching his army through the valleys of the Dublin and Wicklow mountains. At length they reached Glenmalure, a narrow valley, bordered on both sides by steep hills.