Emperor Matthias died on 20 March 1619. Maximilian of Bavaria encouraged Ferdinand to adopt an aggressive policy against the Bohemian rebels, but Ferdinand again confirmed the Letter of Majesty and urged the Bohemians to send delegates to Vienna. The directors ignored Ferdinand's acts and made further preparations for an armed conflict. Wallenstein stormed into Olomouc and seized 96,000 talers from the Moravian treasury on 30 April. He gave the booty to Ferdinand, but the king returned it to the Moravian Estates. The Protestant Estates of Upper Austria demanded the confirmation of their religious and political liberties before recognizing Ferdinand as Matthias' successor. Thurn and his 15,000 troops laid siege to Vienna on 5 June. Since only 300 soldiers were staying in the town, Ferdinand sent envoys to his commander at Krems, Henri Dampierre and entered into negotiations with the Upper Austrian Protestants about their demands. Dampierre and his troops reached Vienna by boat and forced the Protestant delegates to flee from the Hofburg. After Ferdinand's general, Count Bucquoy, defeated the Bohemian rebels in the Battle of Sablat, Thurn lifted the siege on 12 June.