The "DAI" mentioned that Serbs settled the Balkans during the reign of Emperor Heraclius (r. 610–641); however, some research indicates that the Serbian tribe was not part of this later migration (as held by historiography) rather than migrating with the rest of Early Slavs. Through linguistical studies, it is concluded that the Early South Slavs were made up of a western and eastern branch, of parallel streams, roughly divided in the Timok–Osogovo–Šar line. Archaeological evidence in Serbia and Macedonia shows that the White Serbs may have reached the Balkans earlier than thought, between 550 and 600, as many findings of Fibula (brooch)e and pottery at Roman forts point to Serbian characteristics and thus could have represent traces of either part of the Byzantine "foedorati" or a fraction of the early invading Slavs who upon organizing in their refuge of the Dinarides, formed the ethnogenesis of Serbs and were pardoned by the Byzantine Empire after acknowledging their suzerainty. However, it is only from the 610-626 period or the early rule of Heraclius, when the historiography can conclusively refer to the existence of the Serbian state on the Balkans.