In 1920 the Polish Prehistoric Society was set up in Poznań, and its ranks grew. Regional societies became more active and took up research. The founding of an independent Archaeological Commission within the Polish Academy of Learning was evidence of the emancipation of archaeology as an independent research discipline. This move was an attempt to separate archaeology from the Ethnographic and Anthropological Commission. In the first years after independence many new Polish archaeological journals emerged, the most significant of them being Przeglad Archeologiczny (Archaeological Review) and Z Otchłani Wieków (From the Abyss of Ages), both published in Poznań. Of the old ones, Wiadomości Archeologiczne and światowit were still published.

Excavation become more extensive, and the most spectacular discoveries of this time were made in Złota, krzemionki opatowskie, brześć kujawski, Gniezno, and Poznań, including the most significant site—the early Iron Age Hallstatt castle in biskupin, discovered in 1933. It became obvious that accurate pictorial and photographic documentation was indispensable. The importance of surface studies also increased. Archaeology was still between the natural and the historical sciences. A number of regional monographs were written (on Wielkopolska, Silesia, and Pomerania by Kostrzewski, on southeastern Poland by Kozłowski, on Volhynia by Włodzimierz Antoniewicz and Helena Cehak Hołubowiczowa, and on Pomerania by Tadeusz Waga). Monographic syntheses of particular prehistoric periods were written as well, the most significant being the works by Kozłowski on the Paleolithic, Neolithic, and Bronze Ages.

In 1928 Antoniewicz published the first complex synthesis of Polish prehistory, Archeologia Polski (Archaeology of Poland). The interwar period ended with the successive synthesis of the prehistory of Polish land, Prehistoria Ziem Polskich (The Prehistory of the Polish Lands), written under the auspices of the Polish Academy of Learning by Krukowski (for the Palolithic Age), by Kostrzewski (from the Neolithic Age to the great migration period and the Roman period), and by Jakimowicz (for the early Middle Ages). Due to the outbreak of World War II, the work was not published until 1948. It was a classic study that incorporated such concepts as industry, culture, and type as fundamental categories for chronological and spatial classification and for the interpretation of archaeological material.

Other significant influences on the archaeology of this period were the anthropogeographic and the culture-historical schools. Kozłowski indicated the significance of typological method to distinguish particular archaeological cultures; in fact, most of the cultures were identified in the Polish prehistory by this method, and the distinctions remain valid today. Research concentrated mainly on the analysis of archaeological sources and their typology and chronology. Prehistoric archaeology was considered to be part of the history of material culture.

Between the World Wars Polish archaeologists were involved in an academic-political debate with Germans about the ethnic interpretation of certain archaeological cultures, particularly of the Lusatian culture. The dispute was concerned mainly with the origin and beginnings of Slav and German peoples. Archaeologists such as Kostrzewski, Kozłowski, and Tadeusz Sulimirski (1898–1983) argued that the Lusatian culture’s roots were Slavonic. These discussions became particularly fervent after 1933, when Adolf Hitler came into power in Germany.

Museum collections were nationalized to guarantee their stability, and they became the main centers of research. In 1924 the Wielkopolskie Museum, with a large section on prehistory, was founded as the result of the fusion of the Mielz·yński’s Museum and the Provincial Museum (Kaiser Friedrich Museum) in Poznań. Four years later the State Archaeological Museum in Warsaw became the central archaeological museum of Poland.

World War II was a catastrophe for Polish archaeology. Approximately 25 percent of Poland’s archaeologists were killed, and many museum collections and libraries were destroyed. The political situation after the war, when Poland was incorporated in the Soviet zone of influence, ideologized academia, entailing the obligatory acceptance of the doctrine of dialectical materialism. This tendency was particularly strong in the first postwar decade (until 1956), and it did not spare archaeology. The years between 1949 and 1955 were the period