John Keegan 'Leo' Casey (1846 – March 17, 1870), known as the Poet of the Fenians, was an Irish poet, orator, novelist and Republican who was famous as the writer of the song "The Rising of the Moon" and as one of the central figures in the Fenian Rising of 1867. He was imprisoned by the English and died on St. Patrick's Day in 1870.

https://en.wikipedia.org/wiki/John_Kee...