In 953 the "gyula", the second leader in rank of the Hungarian tribal federation, converted to Christianity in Constantinople. Around that time, according to the Byzantine Emperor Constantine VII, the Hungarians controlled the region on the border of modern Romania and Hungary along the rivers Timiş, Mureş, Criş, Tisa and "Toutis". In 1003, as the "Annals of Hildesheim" narrates, Stephen I, the first crowned monarch of Hungary ("c." 1000–1038) "led an army against his maternal uncle, King Gyula", and occupied Gyula's country.