Germans (German: Deutsche) are the natives or inhabitants of Germany, or sometimes more broadly any people who are of German descent or native speakers of the German language. The constitution of Germany, implemented in 1949 following the end of World War II, defines a German as a German citizen. During the 19th and much of the 20th century, discussions on German identity were dominated by concepts of a common language, culture, descent, and history. Today, the German language is widely seen as the primary, though not exclusive, criterion of German identity. Estimates on the total number of Germans in the world range from 100 to 150 million, most of whom live in Germany.
The history of Germans as an ethnic group began with the separation of a distinct Kingdom of Germany from the eastern part of the Frankish Empire under the Ottonian dynasty in the 10th century, forming the core of the Holy Roman Empire. In subsequent centuries the political power and population of this empire grew considerably. It expanded eastwards, and eventually a substantial number of Germans migrated further eastwards into Eastern Europe. The empire itself was generally decentralized and politically divided between many small princedoms, cities and bishoprics, while the idea of unified German state came later. Following the Reformation in the 16th century, many of these states found themselves in bitter conflict concerning the rise of Protestantism.