The
Balaton Principality (also called
Pannonia,
Lower Pannonia,
Pannonian Principality,
Transdanubian Principality or
Slavic Pannonian State, 839/840-876) was a Slavic principality (duchy) located in the western part of the
Pannonian plain, between the rivers
Danube to its east (temporary also included territory in the east of the Danube),
Drava to the south (temporary also included territory in the south of the Drava),
Graz to the west, and
Koszeg or
Klosterneuburg to the north (except for the territory between the
Rába river, the
Balaton and modern
Budapest).
In Slovak, the principality is known as Blatenské kniežatstvo, in Serbian and Croatian as Panonsko Kneževstvo (???????? ??????????), in Hungarian as Balatoni Fejedelemség and at Koppany time Somogy country, and in Slovenian as Spódnja Panónija.
All the above names are modern names, because no name has been preserved from that time. The name "Balaton" is the Hungarian form of the original Slavic name - Blatno ("muddy") or a similar form - for that lake. Frankish sources usually called the territory either simply "Pannonia" or identified it by the name of the then ruler of the principality.
The principality was one of the several Slavic states and groups connecting the areas inhabited by Slavs before they were divided into the northern and the southern Slavs by the conquests of the Franks, the arrival of the Magyars in Pannonia, and later by the expansion of the Romanians.
