The assault focused on the English fort which sat at a bridge on the Blackwater River, marking the border between Counties Tyrone and Armagh.

It was built by Walter Devereux, 1st Earl of Essex, in 1575 as an outpost of English military strength in the heart of Gaelic Ulster, but also to secure the power of the main Irish ally in the region Hugh O'Neill, Baron of Dungannon.

The fort was composed of a square earthwork bawn "twelve score yards in circuit" reinforced by two bulwarks and punctuated with gun loops in its ramparts.

On the morning of Sunday 16 February 1595, Art MacBaron O'Neill approached the fort from the direction of Armagh with 40 men, escorting what appeared to be two prisoners.

As they crossed the bridge one of the English warders noticed the matchcords of the Irishmen's matchlock calivers were lit, a sign that they were ready to fire.

The English, led by Edward Cornwall, were critically low on ammunition but still prevaricated until MacBaron threatened to burn the fort to the ground with all in it.

According to the English commander, O'Neill arrived after the surrender and was outraged at the losses suffered in taking the fort, and was angry that the defenders had not been executed.