His province is believed to have been the territory of Roman Pannonia Savia .
In 829 the Bulgars imposed a local Slavic prince , Ratimir , as the new ruler of Pannonia .
prince 's province is believed to have been the territory of Roman Pannonia Savia .
In 829 the Bulgars imposed a local Slavic prince , Ratimir , as the new ruler of Pannonia .