In 1858 John O'Mahony established the Fenian Brotherhood of America to provide money, arms, and military leadership for an anticipated rising against England by the Irish Revolutionary Brotherhood. An odd twist in this story of nineteenth-century Irish nationalism was the role played by Tennesseans. Between 1866 and 1870, two former Nashville residents rose to top leadership positions in the United States and Ireland, and the Nashville Fenian circle served as a base for a British spy.
Tennessee's Fenian circles emerged during the American Civil War, a period of heavy Fenian recruitment. In 1863 Nashville, already under Federal control, sent delegates to the first Fenian convention in Chicago. Over the years, Nashville maintained a seat in the Fenian senate, and Nashvillian Dennis Murphy was authorized as one of three U.S. agents selling Fenian bonds. Unknown to local Fenians, a British spy, Thomas Billis Beach (known locally as Henri LeCaron), infiltrated the group after the Civil War.
At the 1865 convention the Fenian Council named former Nashville resident Thomas J. Kelly as military representative to Ireland. By 1866 the militant Kelly had replaced Irish Revolutionary Brotherhood founder James Stephens as “Acting Chief of the Irish Republic.” In that same year, a militant branch of the Fenians devised an ambitious plan to capture and hold hostage Canadian territory to force the British to free Ireland. Fenians massed along the Canadian border. On June 1 forces including Nashville's Thirteenth Regiment, led by Nashvillian John O'Neill, crossed into Canada and captured Fort Erie. The next day O'Neill's troops won a minor skirmish at the battle of Ridgeway. Nevertheless, the bold Fenian plan failed, and following days of indecision, President Andrew Johnson issued orders to arrest the Fenians. O'Neill's minor success catapulted him to national prominence as head of the Center of the Fenian Brotherhood. In 1870 O'Neill attempted a second attack on Canada. That failure forced O'Neill's resignation, and he led an Irish-American settlement to Nebraska.