Fenianism was the Irish separatist movement committed to winning Irish freedom through revolution. Defeated often, its tremendous resilience enabled it to rise time and again, phoenix-like, until it eventually inspired the 1916 Easter Rising, soon followed by an Irish War of Independence that finally established an Irish Free State.

The Fenian Rising vividly describes the evolution of the Irish Republican Brotherhood and its American counterpart, the Fenian Brotherhood, two revolutionary organisations dedicated to overthrowing British rule in Ireland and establishing an Irish Republic. Led by James Stephens, nineteenth-century Irelands most important revolutionary, the IRB rapidly became an increasingly serious threat which Dublin Castle struggled unsuccessfully for years to suppress. Despite Stephenss downfall in January 1867 the long-anticipated rising followed two months later.

In spite of its failure, republicans snatched political victory from the jaws of defeat when in September 1867 the execution of the Manchester Martyrs galvanised every shade of Irish nationalism. Rising from the ashes, the IRB survived to eventually become what one historian has called the most enduring and successful revolutionary secret society in Europe.