The Fenian movement (Irish Republican Brotherhood) was a secret society that attempted to achieve Irish independence through insurrection, such as the Easter Rising in 1916, when Britain was involved in World War One.
Editors. "Fenians arrested for planning uprising". The Literary Encyclopedia. First published 01 February 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=5088, accessed 25 November 2015.]