As a result of Yermak's expedition, Russia was able to annex Siberia. During the Polish–Muscovite War (1605–18), the Polish–Lithuanian noble Aleksander Józef Lisowski founded a cavalry mercenary group (named Lisowczycy after his death) from various outlaws, partly Don Cossacks. This group served under the Polish Crown; after the war with Muscovites Lisowczycy took part in the Moldavian Magnate Wars (Battle of Humenné in 23 November 1619) at Upper Hungary, (now eastern Slovakia), later they plundered Silesia and Moravia as allies of Habsburg armies in the Bohemian Revolt – first phase of Thirty Years' War. This phase culminated in the Battle of White Mountain in 8 November 1620 (near Prague, the capital of the Crown of Bohemia, now the Czech Republic), where the Lisowczycy were sent by Johann Tserclaes, Count of Tilly against Hungarian cavalry. They were victorious, capturing twenty standards. After the battle, they terrorised village people around Prague and other cities, so they were expeditiously paid and released from service in 7 May 1621. Some returned to Poland, others served under Habsburg Maximilian I, Elector of Bavaria. Under Peter the Great and subsequent rulers, the Don Cossacks participated in numerous military campaigns, which resulted in the expansion of the Russian Empire from the Black Sea to the Baltic Sea. For years, the Cossacks waged war against the Ottomans and the Crimean Khanate. In 1637 the Don Cossacks, joined by the Zaporozhian Cossacks, captured the strategic Ottoman fortress of Azov, which guarded the Don. The defense of the Azov Fortress in 1641 was one of the key actions in Don Cossack history. After total taking of the Free Territories of Don Cossacks under the Moscovits control, Don Cossack history is totally intertwined with the history of the rest of Russia. In exchange for protection of the Southern borders of medieval Russia, the Don Cossacks were given the privilege of not paying taxes and the tsar's authority in Cossack lands was not as absolute as in other parts of Russia. During this period, three of Russia's most notorious rebels, Stenka Razin, Kondraty Bulavin and Emelian Pugachev, were Don Cossacks.