In 896, his rule stretched from Vienna and Budapest to the southern Croat dutchies, and included almost the whole of ex-Roman Pannonian provinces (whole 4). He probably died 900 fighting against his former allies, the Magyars. The subsequent history of Savia again becomes mirky, and historians are not sure who controlled Savia during much of the 10th century. However, it is likely that the ruler Tomislav, the first crowned King, was able to exert much control over Savia and adjacent areas during his reign. It is indeed at this time that sources first refer to a "Pannonian Croatia", appearing in the 10th century Byzantine work "De Administrando Imperio".