Archaeological evidence on the existence of the Slavic professional soldiers and military leaders in the V-VII centuries is considered. Written sources of this time mention Slavic leaders and talk about Slavic mercenaries, that is, professional soldiers in the Byzantine army. Findings of prestigious armament and equestrian equipment, "professional" weapons, things of the "military" and "princely" culture, as well as the existence of individual burials with weapons and military belts confirm the reports of ancient authors.