The famous work of Professor A.P. Lewandowski about Charles the Great is not only a biography of the first emperor of the West, the founder of the Frankish Empire, but also the history of the formation of the medieval states of Western Europe: France, Germany, Italy. Charlemagne, despite his fame, is one of the most mysterious rulers of the Middle Ages, an era when genealogy issues were crucial to the pretender to the throne: the exact time and place of birth of the future emperor are still unknown. But we can definitely say that it was during the reign of Charlemagne that "Drang nah Ost" began, that hostile onslaught on the Slavs that the West continues to this day. During the reign of this emperor alone, more than 50 military campaigns were made, half of which he led himself.