After a siege of two months Groningen surrendered; and the city with the surrounding district was by the terms of the capitulation--known as "The Treaty of Reduction"-- admitted as a province into the Union under the name of _Stad en Landen._ William Lewis was appointed stadholder, and Drente was placed under his jurisdiction.

The northern Netherlands were now cleared of the enemy, and Maurice at the conclusion of the campaign made a triumphal entry into the Hague amidst general rejoicing.

William Lewis lost no time in taking steps to establish Calvinism as the only recognised form of faith in his new government.

His strong principles did not allow him to be tolerant, and to Catholicism he was a convinced foe.

Everywhere throughout the United Provinces the reformed religion was now dominant, and its adherents alone could legally take part in public worship.
In January, 1595, Henry IV declared war against Spain and was anxious for an alliance with the States against the common enemy.