Duke of Slavonia
The Duke of Slavonia (Croatian: slavonski herceg; Latin: dux Slavoniae), also meaning the Duke of Dalmatia and Croatia (Croatian: herceg Hrvatske i Dalmacije; Latin: dux Dalmatiae et Croatiae) was a title of nobility granted several times in the 12th and 14th centuries, mainly to relatives of Hungarian monarchs or other noblemen. The title of duke of "whole of Slavonia" didn't mean Slavonia in the narrow sense, but specifically all Slavic lands of the Kingdom of Hungary, being a synonym for the Kingdom of Croatia and Dalmatia (and Slavonian domain).