The idea of a Germanic people without sufficient space dates back to long before Adolf Hitler brought it to prominence. Through the Middle Ages, German population pressures led to settlement in Eastern Europe, a practice termed Ostsiedlung. The term Lebensraum in this sense was coined by Friedrich Ratzel in 1901, and was used as a slogan in Germany referring to the unification of the country and the acquisition of colonies, based on the English and French models, and the westward expansion of the United States. Ratzel believed that the development of a people was primarily influenced by their geographical situation and that a people that successfully adapted to one location would proceed naturally to another. These thoughts can be seen in his studies of zoology and the study of adaptation. This expansion to fill available space, he claimed, was a natural and necessary feature of any healthy species.
..... Thus the concept of lebensraum was picked up and expanded by publicists of the day, including Karl Haushofer and General Friedrich von Bernhardi. In von Bernhardi's 1912 book Germany and the Next War, he expanded upon Ratzel's hypotheses and, for the first time, explicitly identified Eastern Europe as a source of new space. According to him, war, with the express purpose of achieving Lebensraum, was a distinct "biological necessity." As he explained with regard to the Latin and Slavic races, "Without war, inferior or decaying races would easily choke the growth of healthy budding elements (Aryans)."
