Who controlled Pannonia after the Roman Empire lost it?

After the Roman Empire lost control of Pannonia at the end of the 4th century, the region was occupied first by various Germanic tribes and subsequently by Slavs.12

The central plains of the region also served as a base for several nomadic peoples migrating from the steppes north of the Black Sea, including the Huns, Bulgars, and Avars. Notably, the Avars maintained dominance over the basin from the 6th through the 8th centuries until they were defeated by Charlemagne around 800 CE. Following the collapse of Avar power, Charlemagne’s successors organized the western portion of the area into a series of Slavic vassal "dukedoms".12