O'Brien, William Smith, Irish patriot; entered Parliament in 1826; sat for Limerick from 1835 to 1843, when he joined the Repeal Association under O'Connell, but separated from it; joined the physical force Young Ireland party, and became the head; attempted an insurrection, which failed, and involved him in prosecution for treason and banishment for life; a free pardon was afterwards granted on promise of abstaining from all further disloyalty; he died at Bangor, in North Wales (1803‒1864).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
O'Brien, William * Obscurantist