At Limerick, under Patrick Sarsfield, the Irish resisted very strongly and William was forced to sign a treaty in October 1691. He agreed to restore religious freedom and other rights to the native Irish in return for the disbanding of Sarsfield's army, some 14,000 of whom went to the Continent where many, including Sarsfeld, joined the armies of France, Spain and other European powers. Over the ensuing 100 years up to half a million Irish, known as the 'wild geese', are believed to have fought in these armies, often forming special brigades or regiments.