 The Greek rulers of Thessaly had long, but erroneously, been known as "Dukes of Neopatras" in Western European sources from their capital, modern Ypati; this was a result of confusion from the family name of Doukas, which Western sources mistook as the title of "duke".As a result, the territory conquered by the Catalans in Thessaly was organized as the "Duchy of Neopatras" and was divided into five captaincies.The Catalans selected the infant Manfred, son of King Frederick III of Sicily, as their duke, but actual power was wielded by the Duke's local representative, the vicar-general, as well as by the marshal ("mariscalus exercitus ducatuum") as the elected head of the Company members.