The House of Andechs was a feudal line of German princes in the 12th and 13th centuries. The counts of Dießen-Andechs obtained territories in northern Dalmatia on the Adriatic seacoast, where they became Margraves of Istria and ultimately dukes of a short-lived imperial state named Merania from 1180 to 1248. They were also self-styled lords of Carniola.

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.