The Archduke Maximilian immediately set camp before the walls of Utrecht and laid siege to the city. His troops' bombardment of the city walls seriously undermined the city's defences and the Hooks quickly requested a truce. Viscount January of Montfoort, the generalissimo Engelbert of Cleves and Gerrit Zoudenbalch then left the city to negotiate terms with the Archduke. The Viscount was not prepared to accept Maximilian's terms without further consultations with his allies so Engelbert of Cleves and Gerrit Zoudenbalch remained behind as hostages whilst Viscount January returned to the city. Shortly thereafter the inconsidered action of a party of Maximilian's troops broke the truce and in reaction January of Montfoort's Hook militants re-commenced hostilities with their besiegers. As a result, both Engelbert of Cleves and Gerrit Zoudenbalch were now considered to be prisoners of war.