The conception of the history of the Polabian Slavs, and the interpretation of tribal structures, has changed several times since the formation of critical historiography. The article set the goal of summarising and expanding on some of the crucial points in historical research into the development of Slavic society in the Polabian area. Since the 19th century, researchers have adhered to the division of Slavs into three groups, Obodrites, Veleti/Lutici and Sorbes, which corresponds with the quantitative use in surviving contemporary sources. These three groups, and the entire tribal organisation, must, however, be put into the context of the history of barbarian Europe. The segmental structure of the Polabian tribes showed some signs of a tribal democracy, and given the military character of individual federations, the whole system could be called a military democracy; but because of the strong ties with religion and religious rites, the current discourse rejects the strict division of military and sacral characters of tribal institutions. Therefore, it is not quite possible to determine whether the tribal organisation of the Polabian Slavs was an equal alternative to Medieval states, as we know from Bohemia, Poland and Hungary.