Vicenza—were left undefended by Pitigliano's withdrawal, and quickly surrendered to Maximilian when Imperial emissaries arrived in the Veneto. Julius, having in the meantime issued an interdict against Venice that excommunicated every citizen of the Republic, invaded the Romagna and captured Ravenna with the assistance of Alfonso d'Este, Duke of Ferrara. D'Este, having joined the League and been appointed Gonfalonier on 19 April, seized the Polesine for himself. The newly arrived Imperial governors, however, quickly proved to be unpopular. In mid-July, the citizens of Padua, aided by detachments of Venetian cavalry under the command of the proveditor Andrea Gritti, revolted. The landsknechts garrisoning the city were too few in number to mount effective resistance, and Padua was restored to Venetian control on 17 July. The success of the revolt finally pushed Maximilian into action. In early August, a massive Imperial army, accompanied by bodies of French and Spanish troops, set out from Trento into the Veneto. Because of a lack of horses, as well as general disorganization, Maximilian's forces were slow to begin the siege of Padua, giving Pitigliano the time to concentrate such troops as were still available to him in the city. Although French and Imperial artillery successfully breached Padua's walls, the defenders managed to hold the city until Maximilian, growing impatient, lifted the siege on 1 October and withdrew to Tyrol with the main part of his army. In mid-November, Pitigliano returned to the offensive, recapturing Vicenza, Este, Feltre, and Belluno; an attack on Verona failed, but Pitigliano destroyed a Papal army under Francesco II of Gonzaga in the process. Angelo Trevisan organized a river attack on Ferrara by the Venetian galley fleet, but the resulting Battle of Polesella ended in another defeat for the Republic when the Venetian ships anchored in the Po River were sunk by Ferrarese artillery. Faced with a shortage of both funds and men, the Senate decided to send an embassy to Julius in order to negotiate a settlement. The terms insisted on by the Pope were harsh: the Republic lost her traditional power to appoint clergy in her territory, as well as all jurisdiction over Papal subjects in Venice, the Romagnan cities that had prompted the war were to be returned to Julius, and reparations were to be paid to cover his expenses in capturing them. The Senate argued over the terms for two months, but finally accepted them in February 1510;