The Republic of Connacht was established by Irish rebels on August 31, during a time of intense conflict known as the Irish Rebellion of 1798. This rebellion sought to address widespread dissatisfaction with British rule and aimed for independence. The involvement of French forces provided both military assistance and ideological support to the Irish faction. The rebels, primarily composed of the Society of United Irishmen, desired a republic based on egalitarian principles, inspired by the French Revolution.

The proclamation of the Republic was made in Connacht, a region in western Ireland that became a focal point for revolutionary enthusiasm. The rebels managed to capture several important towns and were buoyed by initial successes against British troops. However, the fragile alliance with French military forces, hoped to bolster their position, proved to be insufficient for long-term success.

The republic was short-lived, facing immediate resistance from British reinforcements. The lack of a sustainable strategy and the diminutive scale of military resources led to the swift downfall of the Republic, culminating in a series of confrontations and the eventual recapture of territories by British forces. This moment underscored the ongoing struggles for Irish independence and foreshadowed future uprisings throughout the 19th and 20th centuries.