Following some initial successes, particularly in County Wexford, the uprising was suppressed by government militia and yeomanry forces, reinforced by units of the British Army, with a civilian and combatant death toll estimated between 10,000 and 50,000. A French expeditionary force landed in County Mayo in August in support of the rebels: despite victory at Castlebar, they were also eventually defeated. The aftermath of the Rebellion led to the passing of the Acts of Union 1800, merging the Parliament of Ireland into the Parliament of the United Kingdom.