Occupied by the Habsburgs three times (1688–1690, 1717–1739, 1789–1791), headed by the Holy Roman Princes Maximilian of Bavaria and Eugene of Savoy, and field marshal Baron Ernst Gideon von Laudon, respectively, Belgrade was quickly recaptured by the Ottomans and substantially razed each time. During this period, the city was affected by the two Great Serbian Migrations, in which hundreds of thousands of Serbs, led by two Serbian Patriarchs, retreated together with the Austrian soldiers into the Habsburg Empire, settling in today's Vojvodina and Slavonia.