The Gothic War is often viewed as a Pyrrhic victory, which drained the Byzantine Empire of resources that might have been employed against more serious threats in western Asia and the Balkans. In the east, pagan Slavs and Kutrigurs raided and devastated the Byzantine provinces south of the Danube from 517. A century later Dalmatia, Macedonia, Thrace and most of Greece were lost to Slavs and Avars. Some recent historians have taken a different view of Justinian's western campaigns. Warren Treadgold placed greater blame for the vulnerability of the Empire in the late 6th century on the Plague of Justinian in 540–541, which is estimated to have killed up to a quarter of the population at the height of the Gothic War, sapping the Empire of manpower and tax revenues needed to complete the campaign more swiftly. No ruler, no matter how wise, could possibly have anticipated the Plague, he argues, which would have been disastrous for the Empire and Italy, regardless of the attempt to reconquer Italy. However, as a result of Rome having been under attack constantly during the war, the deaths not caused by the plague continued to rise.