As the democratic tendencies and Calvinist excesses were more and more apparent, following the return of Orange to Brussels, the Catholic aristocracy of the Southern provinces became alarmed. The nobles were afraid of the attitude adopted by the people concerning their privileges and of the personal prestige of Orange. They endeavoured to check his power by inviting foreign princes to take the leadership of the country. The Duke of Aerschot induced Archduke Matthias, brother of the Emperor, to come to the Low Countries, but Orange easily countered this manoeuvre by arresting the duke and opening negotiations with Matthias, who signed the second Union of Brussels, on December 10, 1577, and guaranteed liberty of conscience. The young archduke was henceforth a mere figurehead and Orange remained the real ruler of the country.
To add to the confusion, Don Juan opened an offensive, a few days later, and easily defeated the national troops which opposed his progress in Luxemburg, Namur and Hainault, forcing the Government to take refuge in Antwerp. It became more and more apparent that the provinces could not rid themselves of the Spaniards without appealing to foreign help. The Emperor Rudolph being unwilling to support Matthias, the latter had become practically useless. In spite of repeated entreaties, Queen Elizabeth would not consent to give military help. She encouraged the revolution, since it proved a drain on Philip's resources and an efficient protection from Spanish enterprise against England, but she would not openly break with Spain. Only France remained. As early as July 1578, Count de Lalaing endeavoured to repeat with the Duke of Anjou, Henry III's brother, the manoeuvre of Aerschot. He sought, at the same time, to deliver the country from Spain with foreign help and to check the increasing power of Orange and all he stood for in his eyes. Anjou had no respect for the liberties and aspirations of the provinces, neither did his rather tepid religious convictions, as a Catholic prince, stand in his way. He hoped to obtain the title of sovereign of the Netherlands and thus to increase his chances of succeeding in his suit for the hand of Queen Elizabeth.
Once more Orange took for himself the plans propounded by his enemies. He negotiated with Anjou, who received the title of "Defender of the Liberties of the Low Countries" in exchange for some military help. Don Juan was obliged to retreat on Namur, where he died, completely disheartened, on October 1, 1578, leaving his lieutenant, Alexander Farnese, Duke of Parma, to continue the struggle.