qnli question: According to Byzantine historiographers, tribes of Slavs emerged from what areas? sentence: Byzantine historiographers under Justinian I (527–565), such as Procopius of Caesarea, Jordanes and Theophylact Simocatta describe tribes of these names emerging from the area of the Carpathian Mountains, the lower Danube and the Black Sea, invading the Danubian provinces of the Eastern Empire.