The authors present finds (pottery, metal artifacts and so on) from the Early Medieval stronghold, composed of several (two or three) ramparts, take up approx. 7 hectares, at Busówno on the borderland between Poland and Rus'. Then they reconstructed two evolution phases of the mentioned stronghold: (I) before the formation of the state (the beginning of the settlement in Busówno was related to the circular external rampart surrounding an area of approx. 7 hectares (at the present stage of exploration, open settlement at an earlier period cannot be ruled out). Its well-thought-out structure combined defensive elements with protection against the erosive activity of water. The rampart consisted of a low earthen embankment and undetermined wooden constructions filled with earth and reinforced with a stone 'offset'), (II) the first centuries of the state (re-settlement of Busówno resulted in spatial transformation of the town: its functional area and the extent of its development decreased. A large complex covering several hectares was changed into a 3-hectare settlement concentrated around the mound and the northern and western parts of the inner grounds. The interior rampart, traceable only in the eastern and northern part of the complex, probably dates back to that period. Its earthen embankment, the presence of a fascine on its slopes and the lack of traces of reinforcement show that the feature may have functioned as a dam protecting the settlement from seasonal rises of the water level). Busówno in Phase II has been noted in historical sources. The Galych-Volhynian chronicle mentions a Yatvingian raid against Busowno and Ochoz under the year 1234. This extremely important information probably establishes the terminus ad quem for the construction of the stronghold, but it also points to political significance of the place.