Complex sentence: In 1865, when many Fenian leaders were arrested, James Stephens, founder of the Irish Republican Brotherhood, appointed Devoy Chief Organiser of the Fenians in the British Army in Ireland, his duty being to enlist Irishmen in the British Army into the IRB.
Split into simpler sentences: In 1865, when many Fenian leaders were arrested, James Stephens, founder of the Irish Republican Brotherhood (IRB), appointed Devoy Chief Organiser of Fenians in the British Army in Ireland. His duty was to enlist Irishmen in the British Army into the IRB.