Presian may have been young and inexperienced at the time of his accession, and state affairs may have been dominated by the minister ("Kavkhan") Isbul, as under Presian's uncle Malamir. In 837, soon after Presian's accession, the Slavs in the vicinity of Thessalonica rebelled against the Byzantine Empire. Emperor Theophilos sought Bulgarian support in putting down the rebellion, but simultaneously arranged for his fleet to sail through the Danube delta and undertake a clandestine evacuation of some of the Byzantine captives settled in trans-Danubian Bulgaria by Krum and Omurtag.