 A rebellion had been launched by Rory O'More whose forces burnt Naas in 1577.The 40 lords of Laois and Offaly and their families were invited to a peace conference by Sir Henry Sidney on or around New Year's Day 1578; Sidney rose and left the unarmed lords and their wives, children and followers, and all except one were killed by Sidney's men, leaving the castle strewn with body parts and drenched in blood.This killing reputedly of 400 people including 120 O'Mores, virtually the whole O'More family, emptied the country of authority, continuing the English plantations in Queen's County and King's County.