Justin II
After Justinian's reconquest and extensive rebuilding programs, the empire's treasury was left empty. The financial mess weakened the Empire; and forced his successor, Justin II, to suspend payments to the Avars. While the Byzantines were distracted with the Persians, Lombard hordes under king Alboin invaded Italy, and soon conquered most of the peninsula. Later wars with the Persians did not go well in Syria, resulting in mental illness that drove Justin II to his grave.