The Duchy of Merania was a fiefdom of the Holy Roman Empire from 1152 until 1248. The dukes of Merania were recognised as princes of the Empire enjoying imperial immediacy at a time when these concepts were just coming into use to distinguish the highest ranks of imperial nobility.

Istria is the largest peninsula within the Adriatic Sea. The peninsula is located at the head of the Adriatic between the Gulf of Trieste and the Kvarner Gulf. It is shared by three countries: Croatia, Slovenia, and Italy, with 87% of surface area being part of Croatia. Croatia encapsulates most of the Istrian peninsula within Istria County.