Louis invaded Bosnia from two directions in the spring of 1363. An army under the command of Palatine Nicholas Kont and Nicholas Apáti, Archbishop of Esztergom, laid siege to Srebrenica, but the fortress did not surrender. As the royal seal was stolen during the siege, a new seal was made and all Louis's former charters were to be confirmed with the new seal. The army under Louis's personal command besieged Sokolac in July, but could not capture it. Hungarian troops returned to Hungary in the same month. Pope Urban V proclaimed a crusade against the Muslim powers of the Mediterraneum upon Peter I of Cyprus's request on 31 March 1363. Urban V urged Louis to join the crusade, emphasizing that he was a powerful monarch, a devout Christian, and "well-placed to help". The next month the pope levied a three-year tithe on the church revenues in Hungary and asked Louis to support the papal officials to collect the tax. However, Louis made every effort to hinder the activities of the papal tax collectors, stating that he needed resources to cover the costs of his future wars against the infidels and the pope's enemies in Italy.