"The German Empire was founded on January 18, 1871, in the aftermath of three successful wars by the North German state of Prussia. Within a seven-year period Denmark, the Habsb"urg monarchy, and France were vanquished in short, decisive conflicts...At its birth Germany occupied an area of 208,825 square miles (540,854 square km) and had a population of more than 41 million, which was to grow to 67 million by 1914."
Reference: Germany. (2018). In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/high/article/Germany/106260
This section of the Guide provides information on the period in Germany from 1971 to the WWI.