to support Székely, according to the contemporaneous Ambrus Somogyi. When Székely broke into Transylvania in March 1603, Gabriel was the commander of his vanguard. Székelys' troops conquered most fortresses along the Maros and laid siege to Gyulafehérvár. During the siege, the princely palace burned. Székely was installed as prince in May, but Radu Șerban, Prince of Wallachia, annihilated his army near Barcarozsnyó (now Râșnov in Romania) on 17 July. Székely was killed in the battlefield, and his supporters (among them Gabriel) fled to the Ottoman Empire. The Transylvanian refugees started to regard Gabriel as their leader. They sent a delegation to Constantinople in August, asking the permission of the Ottoman grand vizier to elect Gabriel prince and seeking Ottoman assistance to their return to Transylvania. The grand vizier granted the permission, but one of the refugees, Boldizsár Szilvási, prevented Gabriel's election, pointing out that a prince could not be elected by a group of refugees, but by the Diet of Transylvania. Bocskai's supporter Gabriel decided to persuade the wealthy Stephen Bocskai to rise up against Rudolph's commissioners. After royal troops attacked the refugees' camp near Temesvár on 13 September 1604, rumours about the capture of a secret correspondence between Bethlen and Bocskai began circulating. Fearing reprisals, Bocskai withdrew to his fortress at Sólyomkő (now Şoimeni in Romania) and make preparations to resist. He hired irregular Hajdú troops and defeated a royal army on 15 October. Bocskai took possession of Kassa (now Košice in Slovakia) on 11 November. Soon after, Gabriel gave the ahidnâme (or charter) in which the Ottoman Sultan, Ahmed I, styled Bocskai as prince of Transylvania. The delegates of the noblemen and the Székelys elected Bocskai prince on 21 February 1605. According to a letter of Bethlen, Bocskai ordered him to capture "certain castles", for which he had to postpone his marriage in May. Gabriel finally married his bride, Zsuzsanna Károlyi, in August 1605. Bocskai granted the domain of Vajdahunyad (now Hunedoara in Romania) to him. The prince also made him the perpetual ispán (or head) of Hunyad County. Bethlen was a Calvinist. He helped György Káldy, a Jesuit, translate and print the Bible. He composed hymns and from 1625, employed Johannes Thesselius as kapellmeister. Prince of Transylvania In 1605, Bethlen supported Stephen Bocskay and his successor Gabriel Báthory (1608–1613). Bethlen later fell out with Báthory and fled to the Ottoman Empire. In 1613, after Báthory was murdered,