The Dulebs (Dulebes) or Dulebi (Russian: Дуле́бы, Ukrainian: Дуліби) were one of the tribal unions of Early Slavs between the 6th and the 10th centuries. According to the medieval sources they lived in Western Volhynia, today's Southern Czech Republic, and Middle Danube between Lake Balaton and the Mur River (tributary of Drava), probably implying migrations from a single region.
It is considered that the ethnonym existed before the Early Middle Ages because it is usually derived from West Germanic languages. Initially, the Proto-Slavic tribe most probably was part of Przeworsk culture near Old Western Germanic area, and later located in the area of Prague-Korchak culture. Henryk Łowmiański considered the Dulebes, Mazovians, White Croats and Veleti among the oldest Slavic tribes.
The Chronicle describes them as a tribe that formerly lived in what is today Western Ukraine. According to the Primary Chronicle, the Dulebi suffered greatly from the invasion of the Pannonian Avars in the late 6th or early 7th century. Because of it some of them were resettled along the Upper Vltava River in Southern Czech Republic, while others were part of the Slavic settlement of the Eastern Alps.
In 907, the Dulebian unit took part in Oleg's military campaign against Czargrad (Constantinople). It appears that the Dulebi tribal union between 8th and 10th century disintegrated into the Volhynians, Drevlians, Polans, Dregoviches, and possibly Buzhans, eventually to become part of the Kievan Rus'.
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