Fenians were members of a 19th-century Irish nationalist secret society committed to establishing an independent Irish Republic. The movement originated among Irish immigrants in the United States in the 1840s and later had a counterpart in Ireland known as the Irish Republican Brotherhood, founded in 1858. Named after the mythological Fianna, a band of legendary Irish warriors, the Fenians pursued independence through armed rebellion and secret activism. They were involved in several failed uprisings in Ireland and raids into British Canada during the 1860s and 1870s. The movement influenced later Irish nationalism and republicanism significantly. The Fenians' central principle was that Ireland had a natural right to independence, achievable only by armed revolution. Their activities included organizing uprisings, prisoner rescues, and military raids, despite repeated failures due to British opposition and internal challenges. The movement had strong support across Irish communities, particularly among urban workers and rural farmers disillusioned by poverty and political setbacks. The legacy of the Fenians persisted in Irish nationalist politics, notably influencing organizations such as Sinn Féin and the Irish War of Independence.
