At the time of Roman conquest in 9 AD, the territory of the present-day city was largely inhabited by Illyrians (mainly the Dardani) and Celts (the Scordisci). By the late 6th and early 7th centuries, large-scale Slavic raids and settlement began, along with invasions from Hunnic and Germanic tribes. Later, the area would become part of the First Bulgarian Empire. With the weakening of both the Bulgarian and Eastern Roman empires, Stefan Nemanja, Grand Prince of the consolidated medieval Serbian state, captured the territory between 1198 and 1199. Although it is hypothesized that the current area of the city was densely settled by the time of Stefan Nemanja's conquest, it does not appear in medieval Serbian documents.