 Complete the following phrase:  During his reign, Petar kept good relations with both the Byzantine emperor Leo VI the Wise ruled 886912 and the emperor Simeon I of Bulgaria, second son of late emperor Boris, 893-927. He was connected with Simeon by the peace treaty but also with the custom of kumstvo. Strains between Bulgarian and Byzantine empires resulted in the ByzantineBulgarian war of 894896, which was continued as the 