Patrick Sarsfield Cassidy (c1850 - 1903) was an Irish American journalist, poet and revolutionary.
Born circa 1850 in Ireland, in either Dunkineely, County Donegal or Sligo.
He was a pioneering journalist worked as business editor of the New York Sunday Mercury.
He became head of the Fenian Council in 1886 after a power struggle with O'Donovan Rossa in which Rossa accused him of being an agent provocateur for the British.
[1] Cassidy was chiefly famous for his exposure of O'Donovan Rossa.