Submitted thesis deals with selected points from the development of the tribal society of the Polabian Slavs in the area called Slavic Polabia, i.e. the area between the Ore Mountains and the Lusatian Mountains in the south, rivers Elbe and Saale in the west, Baltic Sea in the north and river Oder in the east. The thesis is divided into the introduction and four longer chapters; together, they introduce the forms and manners of the medieval tribal society. The introduction defines the aims and methodology of the thesis, while also emphasizing the necessity to observe the diversity of each tribal societies, even in the context of the Slavic Polabia, which was supposed to be a home of the three big tribal societies or tribal confederations. Because of the differencies in the socio-political development of these three tribal confederations, the first chapter introduced its own proposition of periodization of the Polabian Slavs' history. This proposition is not based on the traditional criteria used by the older and contemporary medieval studies relying on the external factors, level of social differentiation or structural changes in the political system. The proposed periodization set a few development phases, which each of the tribal societies either passed or never reached. In its three parts (head,...