Irish-American Catholics served on both sides of the American Civil War (1861–1865) as officers, volunteers and draftees. Immigration due to the Irish Great Famine (1845–1852) had provided many thousands of men as potential recruits although issues of race, religion, pacifism and personal allegiance created some resistance to service. A significant body of these veterans later used the military experience gained in the war to launch several conflicts with the goal of establishing an independent Irish Republic as members of the Irish Republican Brotherhood, the Fenian Brotherhood and Clan na Gael.
