Gyula (Yula, Gula, Gila) was, according to Muslim and Byzantine sources, the title of one of the leaders, the second in rank, of the Hungarian tribal federation in the 9th–10th centuries. In the earliest Hungarian sources, the title name is only recorded as a personal name (Gyyla, Geula, Gyla, Iula). According to the Hungarian chronicles, Transylvania was ruled by a line of princes called Gyula, and their country was occupied by King Stephen I of Hungary (1000/1001–1038). Etymology The title name has not convincing etymologies, but it is probably of Turkic origin, cf. *yula "torch". The gyulas in the 9th century The first data of the title, recorded by Ibn Rusta and Gardizi, can be traced back to the earlier works of Abu Abdallah al-Jayhani. According to these earliest pieces of evidence, the Hungarians were ruled conjointly by two ‘kings’. The major one, called kende (or künde), enjoyed nominal leadership, while effective power was exercised by his colleague, inferior in rank, called the gyula. This peculiar form of governance (‘dual kingship’) is generally supposed to have been imitative of the Khazar Khaganate, which did indeed have a similar organization. However, the only thing that the Muslim sources tell us is that the gyula was in charge of the military matters of the tribal confederation; whereas there existed a legitimate ruler (the kende) who had little influence on army-related issues. The gyulas in the 10th-11th centuries Following the Hungarian conquest of the Carpathian Basin around 896, the title gyula can be found in the De administrando imperio ("On the Governance of the Empire") written by the Byzantine Emperor Constantine Porphyrogenitus. The emperor confirms that around 950 the gyla was one of the two important officers who assisted the leader of Hungarian tribal federation; also, each tribe had a chieftain. The Byzantine Ioannes Skylitzes in the second half of the 11th century recounted (using earlier written sources) the baptism of the Hungarian chieftain Gyula (or gyula) in Constantinople in the mid-10th century. According to Ioannes Skylitzes, Gyula stayed true to his new faith and took a missionary bishop, Hierotheos, with him. A Slavic source also contains related information. The almost contemporary Annales Hildesheimenses ("The Annals of Hildesheim") recorded for 1003 that "King Stephen of Hungary led an army against his maternal uncle, King Gyula" and "obliged his country by force to adopt the Christian faith". Persons named Gyula in the Hungarian chronicles