The endeavour of Philip to substitute his will for self-government provoked a Catholic and aristocratic opposition, followed by a democratic and Protestant movement, which proved more difficult to deal with. The nobles were overcome by the strong measures of Alva. The Gueux were defeated by Don Juan and Farnese, after the recall of Alva. And it seemed, for many years, that the movement would fail. It is to the statesmanship of William the Silent, who was neither a great soldier nor a strong churchman, that they owed their success. He failed, indeed, to keep Protestants and Catholics together on a wide basis of toleration. In 1579 the southern provinces returned to Spain, and the northern provinces cast off their allegiance. But, by the union of Utrecht, they founded that confederacy which became one of the foremost powers in the world, and the first of revolutionary origin. The southern provinces remained Catholic. The northern were, in great measure, Protestant, but with a large Catholic population. William, the Stadtholder, was killed by an assassin in 1584, before his work was done. He had brought in Alencon, Elizabeth's suitor, that he might secure the help of France. But Alencon proved a traitor; and during the proconsulate of Farnese, Duke of Parma, the Spaniards gained much ground. Philip II stood at the height of his power in the middle of the eighties. He had annexed Portugal, with its immense colonial empire. By the death of Alencon, the King of Navarre, who was a Huguenot, became the heir to the crown of France, and the Catholic party looked to Spain for their salvation. Now, after many patient years, he prepared for war with England. For Drake was ravaging Spanish territory; and an English army under Leicester, having occupied the Netherlands after the death of William, though they accomplished little, gave just cause for an open quarrel. Whenever, in the course of the Counter-Reformation, it came to a duel between Spain and England, the fate of Protestantism would be staked on the issue. That conflict was finally brought about, not by the revolt of the Netherlands, but by the most tragic of all histories, that begins at Holyrood with the murder of Riccio and ends twenty-one years later at Fotheringay.