“These former foes marched side-by-side to undertake one of the most fantastical missions in military history—to hold the Britain’s Canadian colonies hostage.”

By Christopher Klein

THIRTEEN MONTHS AFTER Robert E. Lee surrendered at Appomattox Court House, hundreds of Union and Confederate veterans donned the blue and the gray and grabbed their rifles. The battle-hardened warriors were from both sides of the Mason-Dixon Line, but they had not assembled to reignite the Civil War. Instead, these former foes marched side-by-side to undertake one of the most fantastical missions in military history—to hold Britain’s Canadian colonies hostage and ransom them for nothing less than Ireland’s independence.

Although members of the self-proclaimed Irish Republican Army fought for both the North and the South, they were all bound together by the same Celtic bloodlines. They shared not just an addiction to the smell of gunpowder and the sound of cannon, but a yearning to liberate their homeland from the shackles of the British Empire. And on the night of May 31, 1866, these members of the semi-secret Fenian Brotherhood emerged from the boarding houses, tenements, and saloons of the south side of Buffalo, New York, to attack the British Empire at its closest point—Canada—in a little-known coda to the Civil War.

For 700 years, Britain’s colonial rulers had worked to extinguish Ireland’s religion, culture, and language. And when more than a million Irish died during the country’s infamous potato famine in the 1840s, many pointed to the massive crop failure as an act of genocide. Even 20 years after the disaster, emotions were still raw for many Irish, even among those who’d fled their homeland for America. Now it was time for revenge. Radicalized by their collective ordeal, these Irish American Civil War veterans viewed their service in the bloody crucibles of Bull Run, Antietam, and Gettysburg as training for the fight they really wanted to wage—one to free their motherland.

Keen students of military history, the Irishmen knew that attacking Canada had been as time-honored an American tradition as fireworks on the Fourth of July. The Irish Republican Army followed in the footsteps of American soldiers who beat a well-worn path across the northern border. In fact, even before John Hancock added his signature to the Declaration of Independence, the Con­tinental Army had launched the first major campaign of the American Revolution by storming Quebec. Old-timers in Buffalo could even remember American soldiers mounting three invasions across the Niagara River during the War of 1812. Skirmishes along the border—which was a no-man’s land frequented by counterfeiters and smugglers—flared with regularity.

American anger toward Canada surged during the Civil War, when the British colony became a haven for draft dodgers, escaped prisoners of war, and Confederate agents who plotted raids on border towns, the firebombing of New York City, and even the assassination of President Abraham Lincoln. Given Great Britain’s tacit support for the Confederacy and America’s long-standing designs on Canada under the credo of Manifest Destiny, President Andrew Johnson was more than willing to let the Fenian Brotherhood twist the tail of the British lion. In fact, Washington had sold surplus weapons to the Irish militants, and Johnson met personally with their leaders, reportedly giving them his implicit backing. The Irishmen had been free to establish their own state in exile—complete with its own president, constitution, currency, and capitol in the heart of New York City.

Far from some whiskey-fuelled daydream, the plan for the Irish inva­sion of Canada launched in the spring of 1866 had been carefully crafted for months by veteran Civil War officers, including the one-armed general Thomas William Sweeny. After crossing the Niagara River and the undefended border, the Irishmen encountered British and Canadian forces outside the village of Ridgeway, 20 miles south of Niagara Falls. Although outnumbered, the invaders relied on their considerable Civil War combat experience to rout the enemy at the Battle of Ridgeway, marking the first triumph by an Irish army over forces of the British Empire since 1745.

Following another victory at Fort Erie, the Irishmen were forced to retreat back across the Niagara after President Johnson finally intervened and cut their supply lines. Before withdrawing, the army’s commander, John O’Neill, vowed to return to Canada soon. He would prove true to his word. However, O’Neill’s subsequent attacks in 1870 and 1871—in Quebec and the Prairies—failed miserably and comically.

Yet while O’Neill and his fellow Irishmen could have simply sermonized about the liberation of their homeland as they luxuriated in their freedom in America, they instead offered their blood. They left a legacy of freedom on two continents. Many of them had taken up arms in the Union Army that liberated African Americans from slavery. They were also incidentally responsible for the creation of a new nation; in no small part due to the Fenian Raids, Canada gained the right to self-government in 1867, pointing it toward its ultimate independence.

When a band of rebels declared the establishment of the Irish Republic in the 1916 Easter Rising, their proclamation acknowledged the crucial role of “her exiled children in America.” The Fenian Brotherhood was the first to organize the Irish diaspora into financial and material support that flowed from America to Ireland. It made the United States a player in Anglo-Irish relations—a role that continues to this day in Northern Ireland—and demonstrated that America could provide Irish republicans with a base of operations beyond the legal reach of the British government from which they could raise money, ship arms, and plot military operations.

Although plagued by naïveté, disunity, and indiscretion, the Fenian Brotherhood was a vital link in the chain of history that led Irish republicans to ultimately topple the British lion a half-century later. Their role was acknowledged by future Irish president and prime minister Eamon de Valera upon a visit to O’Neill’s grave in Omaha, Nebraska.

“The Fenian Brotherhood for which General O’Neill fought is the backbone of the Irish republic,” de Valera said. “We have vindicated O’Neill by establishing the republic.”

Christopher Klein is the author of When the Irish Invaded Canada: The Incredible True Story of the Civil War Veterans Who Fought for Ireland’s Freedom (Doubleday, 2019). Learn more at www.christopherklein.com.