After the provinces of the Habsburg Netherlands in 1576 formed a united front against their overlord, king Philip II of Spain, when they concluded the Pacification of Ghent and the Union of Brussels, they soon achieved most of their goals as Philip and his new governor-general Don Juan saw no other option than to accept those treaties and remove the mercenaries of the Spanish Army of Flanders from the country. The rebelling provinces of Holland and Zeeland were reunited with the rest of the country under the government of the States General and the Council of State in which Orange was the leading noble. Under the Pacification of Ghent Calvinists in Holland and Zeeland received freedom of religion next to the Catholic Church that was to remain the dominant religion in the other provinces. But soon Calvinists in other provinces demanded freedom of religion also, and adherents of both religions started to use force against one another. This caused great unrest in the conservative Catholic provinces of the South, like Hainaut and Artois where the Catholic nobility saw its position and that of their church threatened. When the Calvinists grabbed power in several Flemish and Brabant cities, like Ghent, Bruges and Antwerp and started to repress Catholics in those cities, Walloon irregular troops in the employ of the army of the States General mutinied. They became known as "Malcontents", when they seized the city of Menen on 6 September 1578 under the command of Emanuel Philibert de Lalaing, the brother of the stadtholder of Hainaut, Philip de Lalaing, 3rd Count of Lalaing. This "coup" enhanced the reputation of Montigny appreciably among Catholic partisans. and his troops were soon reinforced with the mercenary troops of the Duke of Anjou, who left the country dejectedly in the Summer of 1578. Many of the commanders of the States Army that was destroyed by Parma in the Battle of Gembloux also flocked to Montigny's banner, like Antoine de Goignies, who had become governor of Gravelines for the States General, but was in secret communication with Don Juan From a designation of Montigny's irregulars the word "Malcontents" soon became a kind of "nom de gueux" for partisans of the Catholic cause in general, as opposed to the Calvinist faction, and the moderate "Politiques" around Orange. Montigny and his brother Philip, using Philip's power base in Hainaut, started communications between Parma and the States of Hainaut and Artois, and a number of city governments, under the influence of the governor of Lille, Adrien d'Ognies, seigneur de Willerval. This led to a congress of representatives of those political entities in Arras that on 6 January 1579 subscribed to a declaration in which the "machinations" of the Calvinists and the "weak" religious-peace policies of Orange were denounced, and the participants swore to uphold the Catholic religion and to support each other in this endeavor. This alliance became known as the Union of Arras. Finally, the members of the Union started formal peace negotiations with Parma, which issued in the signing of the Treaty of Arras on 17 May 1579. In a sense this was a triumph of the great nobles who had before 1566 opposed Cardinal Granvelle, but at the price of a permanent breach between the Northern Netherlands and the Southern Netherlands that would soon evolve from the Union of Arras to the Spanish Netherlands.
