Henry III, King of France, (c1820s). Henry (1551-1589) came to the throne in 1574. His reign was dominated by the continuing strife between Catholics and Protestants known as the French Wars of Religion. On 2 August 1589 Henry was assassinated by friar Jacques Clement for his opposition to the Catholic Holy League founded by Henri, Duke of Guise, who had been murdered the previous year, possibly by Henry's order. Clement stabbed the king having been allowed access to him on the pretext of having an important message to deliver.