John O'Leary (23 July 1830 – 16 March 1907) was an Irish separatist and a leading Fenian. He studied both law and medicine but did not take a degree and for his involvement in the Irish Republican Brotherhood he was imprisoned in England during the nineteenth century. Early life Born in the town of Tipperary, County Tipperary, the Catholic O'Leary was educated at the local Protestant Grammar School, The Abbey School, and later the Catholic Carlow College. He identified with the views advocated by Thomas Davis and met James Stephens in 1846. He began his studies in law at Trinity College, Dublin, in 1847, where, through the Grattan Club, he associated with Charles Gavan Duffy, James Fintan Lalor and Thomas Francis Meagher. 1848 rising After the failure of the 1848 Tipperary Revolt, O'Leary attempted to rescue the Young Ireland leaders from Clonmel Gaol, and was himself imprisoned for a week from 8 September 1849. He took part in a further attempted uprising in Cashel on 16 September 1849, but this proved abortive. Irish Republican Brotherhood O'Leary abandoned his study of law at Trinity College, because he was unwilling to take the oath of allegiance required of a barrister. He enrolled at Queen's College, Cork in 1850, to study medicine, later moved to Queen's College, Galway, then on to further studies at Meath Hospital, Dublin, in Paris and in London. In 1855, he visited Paris, where he became acquainted with Kevin Izod O'Doherty, John Martin and the American painter, James Abbott McNeill Whistler. O'Leary subsequently became financial manager of the newly formed Irish Republican Brotherhood (IRB), and was joint editor of the IRB paper The Irish People. Arrest and trial On 16 September 1865, O'Leary was arrested, and later tried on charges of high treason, reduced to 'treason felony'. He was sentenced to twenty years' penal servitude, of which five years were spent in English prisons, prior to his release and exile in January 1871. During his exile, he lived mainly in Paris, also visiting the United States, remained active in the IRB and its associated organisations, and wrote many letters to newspapers and journals. Later life in Dublin On the expiry of his 20-year prison term and therefore of the conditions associated with his release in 1885, he returned to Ireland. He and his sister, the poet Ellen O'Leary, both became important figures within Dublin cultural and nationalist circles, which