It was at this time that those English and Scottish Brigades were first formed which remained for nearly two centuries in that service, and were always to be found in the very forefront of the fighting throughout the great war of Liberation.
On March 4, 1576, Requesens died; and in the considerable interval that elapsed before the arrival of his successor, the outlook for the patriot cause became distinctly brighter.

The Estates of Holland and Zeeland met at Delft (April 25, 1576); and the assembly was noteworthy for the passing of an Act of Federation.

This Act, which was the work of Orange, bound the two provinces together for common action in defence of their rights and liberties and was the first step towards that larger union, which three years later laid the foundations of the Dutch Republic.

By this Act sovereign powers were conferred upon William; he was in the name of the king to exercise all the prerogatives of a ruler.
It required all his influence to secure the insertion of articles (1) extending a certain measure of toleration to all forms of religious worship that were not contrary to the Gospel, (2) giving authority to the prince in case of need to offer the Protectorate of the federated provinces to a foreign prince.

Orange knew only too well that Holland and Zeeland were not strong enough alone to resist the power of Spain.
His hopes of securing the support of the other provinces, in which Catholics were in the majority, depended, he clearly saw, on the numerous adherents to the ancient faith in Holland and Zeeland being protected against the persecuting zeal of the dominant Calvinism of those provinces.