The Ottoman governors of Buda and Temesvár (now Timișoara in Romania) invaded the Hajdú villages in Partium, forcing them to hurry back and defend their homes. Ahmed I granted Wallachia to Radu Mihnea and ordered Gabriel to return to Transylvania in March. Although the sultan's decision outraged Gabriel, he had no choice but to accept it. Radu Şerban ousted Radu Mihnea from Wallachia at the head of an army of Cossack and Moldavian mercenaries. The Diet ordered the mobilization of the Transylvanian army, authorizing Gabriel to collect an extraordinary tax in April. However, Michael Weiss (who had regarded Gabriel as a new Nero) incited the burghers of Brassó to rise up against the monarch. Gabriel dispatched Hajdú captain András Nagy to lay siege to Brassó, but Weiss bribed Nagy to lift the siege. Radu Şerban invaded Burzenland (now Țara Bârsei in Romania) unexpectedly, and routed Gabriel's army near Brassó on 8 July 1611. Gabriel barely escaped from the battlefield to Szeben.