The centre of Catholic reaction might have been formed in any other part of the Southern provinces under similar circumstances. The region of Armentières and Valenciennes had been the cradle of the Iconoclast rebellion, but repression in that quarter was far more effective than in any other. A great proportion of the Walloon workers who did not perish under Alba's rule emigrated to England. The Southern cities were thus considerably depleted of their Calvinist element, and the peasants and the bourgeois outnumbered them far more than in any other part of the country. Even under ordinary circumstances the workers of the towns exercised very little influence on the States of Hainault and Artois. In Hainault (Valenciennes and Tournai forming special circumscriptions), Mons remained alone to represent their interests. In Artois, Arras, St. Omer and Béthune were the only important centres whose representatives could oppose those of the far more important agricultural districts. The question of race and language had no more influence on the attitude of the Walloon provinces than on that of Holland, Zeeland and Utrecht. Both were determined by economic, social and religious conditions as well as by their strategic situation.
The Confederation of Arras was proclaimed on January 6, 1579. On the 23rd the Union of Utrecht was constituted, under the same claim of defending the Pacification of Ghent. It grouped around Holland and Zeeland the provinces of Utrecht, Gelder, Friesland, Over-Yssel and Groningen, together with the most important towns of Flanders and Brabant: Ghent, Ypres, Bruges, Antwerp, Brussels, etc. They undertook to act jointly in reference to peace, war, alliances and all external matters, while retaining their local autonomy. The exercise of religion remained free, with the exception of Holland and Zeeland, from which Catholicism was excluded. The Union of Utrecht was the origin of the Republic of the Seven United Provinces. It was entirely dominated by the particularist policy of Holland and Zeeland, which, as events developed more and more in favour of Farnese in the South, took less and less interest in their Southern confederates. The small forces at their disposal rendered any offensive towards Flanders and Brabant, which would have provided the beleaguered cities with food and arms, very difficult, and the reopening of the Scheldt, which must have taken place in the event of the integral preservation of the Union of Utrecht, would have reacted unfavourably on the trade of the Northern ports.