During late 1596, Michael was faced with an unexpected attack from the Tatars, who had destroyed the towns of Bucharest and Buzău. By the time Michael gathered his army to counterattack, the Tatars had speedily retreated and so no battle was fought. Michael was determined to continue the war against the Ottomans, but he was prevented because he lacked support from Sigismund Báthory and Rudolf II. On 7 January 1597 Hasan Pasha declared the independence of Wallachia under Michael's rule, but Michael knew that this was only an attempt to divert him from preparing for another future attack. Michael again requested Rudolf II's support and Rudolf finally agreed to send financial assistance to the Wallachian ruler. On 9 June 1598 a formal treaty was reached between Michael and Rudolf II. According to the treaty, the Austrian ruler would give Wallachia sufficient money to maintain a 5,000-man army, as well as armaments and supplies. Shortly after the treaty was signed, the war with the Ottomans resumed and Michael besieged Nicopolis on 10 September 1598 and took control of Vidin. The war with the Ottomans continued until 26 June 1599, when Michael, lacking the resources and support to continue prosecuting the war, signed a peace treaty.