Fenian

Fenian refers to members of 19th-century Irish nationalist organizations that advocated independence from the United Kingdom. The term derives from Fianna, the legendary band of Irish heroes in Irish mythology. In Ireland, the Irish Republican Brotherhood (IRB) was founded in 1858 as a secret society dedicated to establishing an independent Irish republic by force. In the United States, the Fenian Brotherhood formed around the same period as a sister organization linked to the IRB, with leaders including John O'Mahony and Michael Doheny. The two groups coordinated activities and shared aims beneath the broader Fenian movement.

The Fenians carried out armed campaigns, including the 1867 Fenian Rising in Ireland, which aimed to trigger a larger rebellion but was quickly suppressed. They also conducted invasions of British North American territory, known as the Fenian raids, during the mid-1860s to early 1870s, in an effort to pressure Britain on the issue of Ireland.

Following government repression and internal divisions, the movement declined by the late 1860s and 1870s. The IRB continued as a clandestine organization, while the Fenian Brotherhood dissolved. The Fenian label persisted in popular usage to describe Irish nationalists and volunteers who opposed British rule, and the broader Fenian legacy influenced later strands of Irish republicanism, including 20th-century movements seeking independence.