Irish nationalist society active chiefly in Ireland, the U.S., and Britain, especially in the 1860s.
The name derived from the Fianna Éireann, a legendary band of Irish warriors led by Finn MacCumhaill . Plans for a rising against British rule in Ireland miscarried, but in the U.S., Fenians staged abortive raids into British Canada and caused friction between the U.S. and British governments. The Irish wing was sometimes called the Irish Republican Brotherhood, and as such continued after Fenianism died out in the early 1870s. See also Sinn Féin .