27th , 1830
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.
1848 rising
Denis Dowling Mulcahy, Thomas Clarke Luby and John O’Leary 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.