Research concerning the history of government and administration should be based not only on historical documents (like legal acts) but also narrative or literary sources such as chronicles. These texts contain large amounts of information about old forms of administration. A good example of that kind of narrative source is the description of European Sarmatia written by Alessandro Guagnini. The author of this text was Italian, who lived in the PolishLithuanian Commonwealth at the turn of sixteenth and seventeenth century. This text was a historical and geographical relation about the Polish-Lithuanian Commonwealth and its neighbours. It was reprinted in different editions and in few languages having a considerable impact on a perception of abovementioned state and even Central and Eastern Europe as well. In modern times Guagnini's works have been quite forgotten, nevertheless its renewed analysis leads to interesting information at various levels. One of them is presentation of government model in the Polish-Lithuanian Commonwealth. The described state consisted of few great regions each of which had its own administrative division, history and customs. Together they merged into a great political entity ruled by one monarch and approaching unification. The purpose of this article is to present administrative division in the pages of the described chronicle and how that division was ideologically legitimated by appealing to ancient Sarmatia.