This work is a contribution to clarifying the causes of population growth in the 19th century in Central Europe. Based on the concept of epidemiological transiti-on, it examines the question of whether the spectrum of diseases with fatal out-come has changed in the transition to modern times. It is based on a solid data basis. The death registers of the County of Schaumburg from the 17th to 19th centuries were evaluated. The historical-demographic investigation of the indivi-dual causes of death was carried out according to a fixed scheme; their presentati-on is based on the category of age. To verify the results, both contemporary and modern medical literature were used.With a very high degree of probability many causes of death could be attributed to specific diseases or disease groups such as chronic and acute respiratory dise-ases. Changes in mortality trends and, in some cases, even their causes can be un-derstood. There is an interaction between climate and mortality. Apart from infant mortality, the nutrition factor plays only a minor role. In addition, it could be shown that the causes of death, particularly in the context of infant mortality and fatal injuries, allow conclusions regarding aspects of everyday life and mentality in the past. Insights into the human influence on the development of mortality in the past were also collected. The Schaumburg population benefited from the still mo-dest progress made in medicalization.During the period investigated the county of Schaumburg was an exclave of the Landgraviate of Hessen-Kassel, but formed a closed territory. The basic part of this study extensively covers the political, economic and social structures of the County of Schaumburg. Special consideration is given to various aspects of de-mographic development in the transition to modern times. This study therefore also closes a research gap in northern Germany.