When Henry shifted from neutrality to opposing France in Brittany and Flanders, thereby reviving the Anglo-Burgundian-Breton axis against France, it was Charles VIII who supported Yorkist conspiracies to neutralise Henry and punish him for his ingratitude. In 1490–91, the French encouraged two failed plots to murder Henry VII, and then they became involved with a new Yorkist impostor, Perkin Warbeck, who appeared in Ireland in late 1491 masquerading as Richard, duke of York, Edward IV’s youngest son. Charles VIII’s support for the impostor was a factor in Henry’s 1492 war against France, and included in the treaty of Étaples was Charles’s promise not to support Henry’s rebels. After the peace was signed, Charles expelled Warbeck from France.