Battle of the Boyne between James II and William III, 11 June 1690 by Johan van Huchtenburg When the English king James II fathered a Catholic heir, leading Protestants turned in desperation to Prince William III for aid. The Dutch Protestant stadholder was James's son-in-law. Fearing an alliance between the Catholic French and English monarchs William's response was positive. In 1688 he gathered an army and crossed over to England. Deposed, James II continued the fight with French aid in Ireland, only to be defeated in 1690 at the Battle of the Boyne. Left: the hard-fought bridge over the Boyne in Drogheda. Perhaps the horseman in the centre (on the white horse) is William III.