This contribution examines the origin legend of the First Bulgarian Empire, one of the most important early medieval polities in Southeast Europe, which existed between 681 and 1018. The legend seeks to explain the settlement of the Bulgars south of the Danube at the end of the seventh century. It recounts the story of a ruler named Kubrat, who lived in the region north of the Black Sea, and his five (in some versions three) sons. Despite his wish that they remain united after his death, the sons part ways and lead their respective groups to different regions. One of them is said to have founded the Bulgarian polity, while the son who remains is subdued by the Khazars. In contrast to many other origin legends of the period, this narrative is often treated as reflecting historical events, with both Kubrat’s polity and the subsequent division of his sons frequently taken at face value. The paper analyses different versions of the story as transmitted by authors such as Theophanes Confessor, Patriarch Nikephoros, and Michael the Syrian, among others. These versions differ in their dating of the events, the number of sons, and the routes taken during the migration. The paper also explores possible connections between these accounts. Notably, the motifs employed – such as the division of brothers and the geographical setting – appear frequently in other contexts, where they are associated with different periods, peoples, and events. The paper argues that, rather than using the narrative to reconstruct historical events, it is more productive to reverse the perspective and interpret the story as an attempt to condense complex processes of migration and political transformation into a familiar and coherent narrative. In this sense, the legend can be understood as an explanatory framework designed to account for the appearance of similarly named groups, the Bulgars, across different regions of the Mediterranean and Eastern European world.