Bulgarian relations with its neighbors during his reign were marked by long marches, swift military raids and exhausting battles. The neighboring Byzantine Empire had been ailing in rebellions of Slavic tribes within the empire and years of battles against Arabs. Presian Khan chose Kav-Khan Isbul, an aide of his grandfather Omurtag, in charge of the Bulgarian expanision into Macedonia and Byzantine territories in the southwest. In 837, Presian sent his army under the command of Kav-Khan Isbul to the Aegean coast of Macedonia. In Western Khodopes and Aegean Thrace, they aided the Smolyans, whose revolt had shaken Byzantium. Fierce battles ensued at Philippi and Siar, expanding the Khan's territory.
Presian was defeated in the war from 839 to 842 against the Serbs. The first war ever between the two neighbors did not, however, result in loss of territory. Khan Presian brought together the Slavs from Moesia, Macedonia and Thrace. Annexing territories in Western and Central Macedonia, Kosovo Polje also became part of Bulgaria. Thus he achieved long-sought political unity for the "Bulgarian" group.
and possibly Malamir
|List of Bulgarian monarchs||
Boris I Michael