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.

The soldiers were climbing one of the slopes, so precipitous that it was impossible for them to keep their ranks, when the enemy opened fire on them, from behind the bushwood and low trees with which the ground was covered. Weary and out of breath, the English made little resistance, but fled in disorder. Some 800 fell, and the remnant was led by Grey back to Dublin. As was usually the case after an Irish victory, revolts broke out in all directions, not only amongst the Leinster septs, but also in South Ulster. Just at this juncture, news reaching the Deputy that a Spanish force had landed at Kinsale to help the Munster rebels (October 1st, 1580), he was obliged to abandon, for the present, the idea of prosecuting the war in Leinster, and to march south.

The force which had been sent to the assistance of the Desmonds consisted of only about 800 men, of whom the majority were Spaniards, the rest chiefly Italians. The little army took up its position in the fortress of Dunanore, previously occupied by James Fitzmaurice. This fortress, though small, was reckoned a strong one, yet, after a siege of only a few days, it was yielded up by San Josepho, the Spanish leader. That their lives were promised to the defenders is not quite certain, but seems highly probable. It is scarcely credible that they should have surrendered unconditionally, as they had an abundant supply of ammunition and provisions. If, however, conditions were made, they were not observed.

What occurred after the surrender, Grey himself relates: ” When morning came, the Colonel came with ten or eleven of his chief gentlemen, trailing their ensigns rolled up, and presented them to me with their lives and the fort … I sent straight certain gentlemen in to see their armour and weapons laid down. Then I sent in certain bands who straightway fell to execution.” The number slain was over 600. The lives of San Josepho and of a few of his chief officers were spared in the hope of ransom.

This massacre does not appear at the time to have excited much disapproval. The Queen was highly pleased with it apparently, as she wrote a letter of thanks to the Lord Deputy. Philip of Spain seemed chiefly desirous to disclaim all responsibility for an enterprise which had failed so signally.