Annexation to Poland of the so-called The Recovered Territories in 1945 was an impulse for creating new tasks for Polish historical sciences. And the history of the Polish state was so arranged that the Middle Ages had the greatest potential for searching for national traditions. Polish scientists, who took steps to create scientific, museum and conservation structures in these areas, also began researching the past of these lands. For many of them this was unknown territory, they had almost no publications on this subject. They had to face the results of earlier German work, developing a new Polish narrative about the past. A similarly pioneering stage took place in the work on securing monuments and remnants of the cultural heritage of these areas. The community of archaeologists, historians, art historians and conservators was not numerous in pre-war Poland, and many died during the war.

We use many concepts and metaphors to facilitate understanding and explanation of the past In historical narrative. One of the ideas rooted in Polish historiography is the Piast idea, which is a kind of narrative metaphor. It functions as an element of a broader narrative that praises nativeness - starting with the Slavic idea, through the Piast idea, ending with Polishness. Building national identity required and requires appropriate treatment of the founders of the state - the first Piasts, those domini naturales. The concept of Piast Poland began to play an important role in the work of historians in the 19th century, although it had already existed in historical literature earlier. Historians such as O. Balzer, Z. Wojciechowski and W. Semkowicz played an important role in its construction. Building national identity based on the Piast idea took the form of the official historical policy of the Polish state after 1945. Silesia, which was then annexed to Poland.