modern historians assume that Bocskai boosted Gabriel's career in Sigismund Báthory's court, but no contemporaneous document mentioned his presence in the prince's retinue. Sigismund Báthory joined the anti-Ottoman Holy League of Pope Clement VIII and broke into Ottoman territory in the summer of 1595. According to historian József Barcza, Gabriel gained his first direct experience of warfare fighting against the Ottomans in the Battle of Giurgiu in Wallachia in 1595. After a series of Ottoman victories, Báthory abdicated in return for the Silesian duchies of Opole and Racibórz in 1597, enabling the commissioners of the Holy Roman Emperor, Rudolph (who was also king of Royal Hungary) to take possession of Transylvania. Anarchy Sigismund Báthory regretted his abdication and returned to Transylvania in August 1598. He sent Bocskai to Prague to start negotiations with Rudolph in January 1599. According to a scholarly theory, Gabriel Bethlen accompanied Bocskai to Prague. Historian József Barcza also says, Gabriel must have realized around that time that the Habsburg monarchs were unable to defend Transylvania against the Ottomans. Gabriel himself stated that he visited Prague in the retinue of Sigismund Báthory at an unspecified date. Gabriel supported Andrew Báthory, who mounted the throne with Polish assistance after Sigismund again abdicated in 1599. Michael the Brave, Prince of Wallachia, broke into Transylvania and defeated Andrew in the Battle of Sellenberk (at present-day Șelimbăr in Romania) on 8 October 1599. Gabriel received wounds in the battle and his wounds healed slowly. Michael the Brave was expelled from Transylvania by Rudolph's commander, Giorgio Basta. During the following years, Transylvania was regularly pillaged both by Basta's unpaid mercenaries, and by Ottoman and Crimean Tatar troops. Gabriel and his brother, Stephen, divided their inherited estates, with Gabriel receiving Marosillye. Their agreement also refers to the anarchic situation, mentioning the possibility that "either pagan or some godless prince or the governor" would seize Gabriel's property. Gabriel joined the Transylvanian noblemen who rose up against Basta. Sigismund Báthory (who had again returned to Transylvania) granted Gabriel and his brother landed property in Arad County in June 1602. The army of the rebellious noblemen was annihilated near Tövis (now Teiuș in Romania) on 2 July 1602. After the battle, he swam over the Maros River and fled to Temesvár in the Ottoman Empire (now Timișoara in Romania). He forged letters which suggested that the leading Transylvanian noblemen supported Moses Székely to persuade the Ottomans