Pannonia or Pannoniae is a name of an ancient Roman province in central Europe. In the 1st century BC, Roman emperor Octavian Augustus expanded his empire to the north up to the Danube river, and founded the province Illyricum, which was later split into Pannonia in the north and Dalmatia in the south. Pannonia occupied modern-day's western Hungary, northeastern Croatia (Slavonija) and northern Serbia (Vojvodina).
In the 2nd century AD, Trajan divided the province into Pannonia Superior ("Upper", really in the west, with capital in Carnuntum (near Vienna)) and Pannonia Inferior ("Lower", really in the east, with capital in Aquincum (near Budapest)). Later, Diocletian subdivided the province into four parts:
- Pannonia Prima in the northwest, with capital in
- Pannonia Valeria in the northeast, with capital in Sopiane (Pecs),
- Pannonia Savia in the southwest, with capital in Siscia (Sisak),
- Pannonia Secunda in the southeast, with capital in Sirmium (Sremska Mitrovica)
Diocletian also moved parts of today's Slovenia out of Pannonia and into Noricum. The intricate details of the border lines would probably bore everyone to death :-)
The native inhabitants of the area were Illyrians (Celts), which often rebelled against the Roman oppression, so the Romans had to build several fortified cities; other than the aforementioned capital ones, notable cities were Scarbantia (Sopron), Arrabona (Gyor), Gorsium-Herculia (Szekesfehervar), Mursa (Osijek), Cibalae (Vinkovci), Marsonia (Slavonski Brod), and Taurunum (Zemun).
In the 4th century, the province was invaded by the Huns who were eventually replaced with other moving barbaric tribes such as the Avars in 6th, Slavs in 7th and Magyars in the 9th century, who settled in this rich, fertile land.
Nowadays, the term Pannonian is often used to described the whole flat area in the center of which is Hungary.
There is also a notion of a Pannonian Sea which existed in ancient Earth history, that covered the today's lowlands, and which eventually dried out and left us with the river Danube and its many affluents (such as Drava, Tisa and Sava).