In 1584, Philip signed the Treaty of Joinville with the Catholic League of France to stop the rise of Protestantism there. In the Spanish Netherlands, England had secretly supported the side of the Dutch Protestant United Provinces, who were fighting for independence from Spain. In 1584, the Prince of Orange had been assassinated, leaving a sense of alarm as well as a political vacuum. The following year was a further blow to the Dutch with the capture of Antwerp by Spanish forces led by Alexander Farnese, the Duke of Parma. The Dutch rebels sought help from England, which Elizabeth agreed to as she feared that a Spanish reconquest there would threaten England. The Treaty of Nonsuch was signed as a result – Elizabeth agreed to provide the Dutch with men, horses, and subsidies but she declined overall sovereignty. In return, the Dutch handed over four Cautionary Towns which were garrisoned by English troops. Philip took this to be an open declaration of war against his rule in the Netherlands.