In 1798, revolution was in the air. Even in the remote fastness of rural Ireland the news had spread that the French had beheaded their king and declared a republic founded on the principles of liberty, fraternity and equality. Better yet, the American colonies had cast off the yoke of British rule in favor of government of the people, by the people and for the people.
That all sounded promising to a faction of Irish rebels known as the United Irishmen. By that time the Irish had been under the thumb of the English throne for 600 years. The United Irishmen secured the support of French military intervention, and Gen. Jean Joseph Amable Humbert showed up with the promised troops. Together the French and Irish forces won a major battle at Castlebar in County Mayo. Sounds promising, but the British viceroy of Ireland at the time? One Lord Cornwallis.
Cornwallis was still stinging from the drubbing he'd received across the Atlantic at the hands of George Washington. In fact, it was Cornwallis who surrendered to the colonial forces at Trenton, New Jersey, bringing the American War for Independence to an end. The viceroy wasn't about to endure the humiliation of losing another major colony. He hired enough mercenaries to defeat the Irish rebellion, snuffing out the Republic of Connacht just 12 days into its existence [source: World Heritage Encyclopedia].