The Management of Research on the Beginnings of the Polish State was established to carry out extensive, interdisciplinary research on the genesis and functioning of the state of the first Piasts, which was undertaken in connection with the need to celebrate the 1000th anniversary of the Polish state and its baptism. In 1949–1953, Early Medieval archaeological sites were examined in 31 cities. The most attention was devoted to strongholds with Piast records (Gdańsk, Gniezno, Giecz, Poznań, Kruszwica, Kalisz, Tum pod Łęczycą, Błonie, Bródno, Wrocław, Opole, Niemcza, Cieszyn, and Wiślica). Most of them are located in the medieval centres of modern cities. In this situation, the natural order of things was to link the problems of Early Medieval castles with the problems of the beginnings of Polish cities. Early Medieval sites in Poland, usually with a complicated stratigraphy, especially in the case of cities or strongholds, are the most difficult to excavate. Meanwhile, at that time only limited experience of excavation work at multi-layer sites prior to World War II was available – as a consequence, research methods for larger settlement complexes were developed on an ongoing basis, in the course of the research itself. Thus, the Millennium program has become a kind of testing ground in the field of urban archaeology in Poland. Key word: history of Polish archaeology, Management of Research on the Beginnings of the Polish State, millennium archaeology, urban archaeology.