 However, during this campaign the Bulgarian army conquered most of Macedonia including Philippi, where the inscription was found.From that point on, Isbul disappears from the sources, and there is no information about the date and circumstances of his death.In his biography of Isbul, Pavlov underlines his "extraordinary merits for the development of the Bulgarian state" and describes him as "one of the architects of medieval Bulgarian statehood during the years of its rise".