A non-invasive exploration of the stronghold at Dzięcioły, Łosice County, in NE Poland began in 2018 (Fig. 1, 2). Based on the results of test excavations from 1968, the stronghold was dated to the 12th century. Its three-line defence system consists of fortifications on the outside of the suburbium, the stronghold proper, and the small ringfort located on its inner grounds. Also visible are such elements as the remnants of supposed gateways, earthen ramps across the moats, and a dyke leading from the stronghold towards the river (Fig. 3, 4), allowing movement inside and outside the settlement. The dating of the site and related determination of its function are the most important research problems. The existing chronology, based on a traditional archaeological analysis, does not allow for the correct conclusions. The situation is complicated by the fact that the site at Dzięcioły consists of three separate sets of fortifications, with one of them (the central one) exceptionally developed, comprising two ditches and three concentric embankments. As the site has not been excavated, its chronology can only be inferred by noticing several possibilities for relative dating. There is a hypothesis that the stronghold at Dzięcioły is a remnant of the early medieval settlement of Łosice, translocated in the High Middle Ages to a settlement of the same name established nearby, first mentioned in the first half of the 15th century. However, analysis of the sources indicates that the stronghold at Dzięcioły may have been abandoned at the end of the first half of the 13th century, when the basin of the Middle Bug River became a target for armed invasions. This possibility has been confirmed preliminarily by the results of geophysical prospection. Alternatively, the stronghold at Dzięcioły could have been abandoned in the first quarter of the 14th century due to a change in the geopolitical situation in the region. As a result, the early medieval road network lost its dominant position, and the previously secondary routes increased in importance. It was on such a route that the new settlement of Łosice was established. It could have taken over the strategic functions previously served by the stronghold at Dzięcioły. Indirect data in this respect is provided by the results of onomastic research. The connection between the early medieval stronghold and the chartered town is also indirectly evidenced by information about the Church of the Dormition of the Blessed Virgin Mary, which was supposed to exist in Łosice as early as in 1264. The church could have been located in the stronghold before it was abandoned and later moved to the ‘new’ Łosice. The geophysical prospection carried out at the site revealed the presence of a rectangular anomaly measuring about 19×16 m, situated in the courtyard of the inner ringfort. The anomaly is interpreted as the remains of a burnt, wooden or wood-and-brick structure. Preliminary examination of the phenomenon of translocation indicates that in Mazovia and the areas of the Polish-Ruthenian/Polish-Lithuanian borderland, it happened it two stages. The older phase can be dated from the second half of the 10th century to the 12th century and is associated with the establishment of a stronghold network of the early state. This process is illustrated by examples from Old Mazovia and its borderland with Kievan Rus’. The stronghold network of the region survived at least until the end of the 12th or mid-13th century, when the second stage of translocation changes began. The strongholds were abandoned, and non-fortified settlements, which took over their functions, were established in the vicinity. Their proto-city status might have been further conditioned by the organisation of trading sites. The settlements were then situated at key points of travel routes, resulting in the development of local exchange in the context of long-distance trade. Due to dynamic economic and demographic development, these settlements were granted city rights in the 15th and 16th century.