The transition to a modern society was substantially complete in the Netherlands by about 1920, right across the board. By that is meant that the most important structures of twentieth-century society were in place, and that change was advanced in all relevant fields. Some of them were virtually complete – like the extension of the franchise – while others still had some of their most important developments to come – as in the case of the welfare state. But most of the essential features of modern Dutch society of the twentieth century had emerged, and the transition period was essentially in the past by the end of the First World War.

The population had experienced astonishing growth, mainly owing to plummeting death rates. Fertility rates were very high, and were to remain so for some time. From the 1870s the environmental problems which had helped cause very high mortality were being brought under control, assisted by increasing levels of prosperity and improved nutrition after 1850. Cultural as well as economic factors were of importance in the demographic situation, especially those inspired by the churches. The Dutch diet in both quantity and quality had taken on distinctly modern characteristics in terms of nutrition and variety by the time of the First World War, and so assisted the fall in mortality and brought the causes of death more recognizably into line with those familiar in the later twentieth century.