The Irish Brigade (, ) was a brigade in the French Royal Army composed of Irish exiles, led by Lord Mountcashel. It was formed in May 1690 when five Jacobite regiments were sent from Ireland to France in exchange for a larger force of French infantry who were sent to fight in the Williamite War in Ireland. The regiments comprising the Irish Brigade retained their special status as foreign units in the French Army until nationalised in 1791. Formation When King James II went to Ireland in March 1689, Ireland was ruled by his viceroy Tyrconnell and was held by the Irish Army, which was loyal to King James. There seemed to be no need for the deployment of French troops in Ireland and Louis XIV needed his troops elsewhere during the Nine Years' War. When the Irish Army showed its weakness by failing to win the Siege of Derry and losing the minor Battle of Newtownbutler on 31 July 1689, Lauzun was sent to Ireland with a French force of 5000 men but Ireland had to send Irish troops to France in exchange. This was the Irish Brigade, formed in May 1690. It consisted of five regiments, comprising together about 5000 men. The regiments were named after their colonels: Lord Mountcashel, Butler, Feilding, O'Brien, and Dillon's Regiment, commanded by Arthur Dillon. The French reformed them and disbanded Butler's and Feilding's, incorporating their men into the remaining three regiments, which were: Mountcashel's O'Brien's, and Dillon's These three regiments formed the first Irish Brigade in France and were known as Lord Mountcashel's Irish Brigade and served the French with distinction during the remainder of the Nine Years' War (1689–97). Under the terms of the Treaty of Limerick in 1691, which ended the war between King James II and VII and King William III in Ireland, a separate force of 12,000 Jacobites of the Irish Army had arrived in France in an event known as Flight of the Wild Geese. These were kept separate from the Irish Brigade and were formed into King James's own army in exile, albeit in the pay of France. Dorrington's regiment, later Rooth or Roth, following the Treaty of Ryswick in 1698, was formed from the former 1st and 2nd battalions James II's Royal Irish Foot Guards (formerly on the Irish establishment) of Britain. Service With the Treaty of Ryswick in 1697, King James's army in exile