In 1645, Parliament organised its soldiers into the New Model Army. The Earl of Essex was replaced by Sir Thomas Fairfax. Oliver Cromwell became Fairfax's deputy. The New Model Army was better organised than any army that had come before it. They defeated the King's largest army at the Battle of Naseby in June 1645. Most of the Royalist soldiers at Naseby were taken prisoner.</small> King Charles escaped Naseby but left behind his baggage, which had letters inside them. The Parliamentarians opened them and found out that the King was trying to get help from the Irish Catholics and from Catholic countries. The King lost support because of this.