Complex sentence: Starting in the very early Middle Ages, the area was mostly ruled by the County of Tyrol or the Bishopric of Brixen, both belonging to the realms of the Austrian Habsburg rulers, while the area of Cadore was under the rule of the Republic of Venice.
Split into simpler sentences: Starting in the very early Middle Ages, the area was mostly ruled by the County of Tyrol or the Bishopric of Brixen, both belonging to the realms of the Austrian Habsburg rulers. The area of Cadore was under the rule of the Republic of Venice.