Complex sentence: Cashman strongly supported Cogadh na Talún and agrarian agitation in Ireland, so in 1881 he published the first biography of Michael Davitt, one of the founders of the Irish National Land League.
Split into simpler sentences: Cashman strongly supported Cogadh na Talún and agrarian agitation in Ireland. In 1881, he published the first biography of Michael Davitt, a founder of the Irish National Land League.