Essex, whose mind was a prey to apprehension from his enemies in England had demanded reinforcements before he could undertake anything against Ulster. It seems hardly credible that the 15,000 regular troops in the country at his coming should be mostly taken up with garrison duty, yet we cannot otherwise account for their disappearance from the field. He asked for 2,000 fresh troops, and while awaiting their arrival, sent a detachment of 600 men into Wicklow, who were repulsed with loss by Phelim, son of Feagh, the new Chief of the O'Byrnes. Essex was thrown into transports of rage at this new loss. The officers who retreated were tried by court-martial, and, contrary to his usually generous temper, the surviving men were inhumanly decimated.
Early in September, the reinforcement he had asked for arrived with a bitterly reproachful letter from the Queen. He now hastened to make a demonstration against Tyrone, although, from some cause unexplained, he does not seem to have drawn out the whole force at his disposal. From Newry he proceeded northward towards Carrickfergus, with only 1,300 foot and 300 horse. On the high ground to the north of the river Lagan, overlooking Anaghclart Bridge, he found the host of O'Neil encamped, and received a courteous message from their leader, soliciting a personal interview. Essex at first declined, but afterwards accepted the invitation, and at an appointed hour the two commanders rode down to the opposite banks of the river, wholly unattended, the advanced guard of each looking curiously on from the uplands. O'Neil spurred his horse into the stream up to the saddle girth, and thus for an hour, exposed to the generous but impulsive Englishman, the grievances of himself and his compatriots. With all the art, for which he was distinguished, he played upon his knowledge of the Earl's character: he named those enemies of his own whom he also knew to be hostile to Essex, he showed his provocations in the strongest light, and declared his readiness to submit to her Majesty, on condition of obtaining complete liberty of conscience, an act of indemnity to include his allies in all the four Provinces; that the principal officers of state, the judges, and one half the army should in future be Irish by birth. This was, in effect, a demand for national independence, though the Lord Lieutenant may not have seen it in that light. He promised, however, to transmit the propositions to England, and within presence of six principal officers of each side, agreed to a truce till the 1st of May following. Another upbraiding letter from Elizabeth, which awaited him on his return to Dublin, drove Essex to the desperate resolution of presenting himself before her, without permission. The short remainder of his troubled career, his execution in the Tower in February, 1601, and Elizabeth's frantic lamentations, are familiar to readers of English history.