The process of gradual transformation from a traditional feudal to a modern economy, which had been going on for over half a century in all of Europe, and at a slower pace in southeastern Europe, came to a temporary halt with the First World War. The economic structure of East-Central Europe which took shape after the end of the war and the revolutions that immediately followed cannot be regarded simply as a continuation of that of the prewar period. Postwar alterations such as the disappearance of former regional economic units, the enormous decrease or increase in the size of various territorial entities and in the number of inhabitants of a given state, and the creation of new states out of lands that had belonged to different empires and which represented different levels of development produced basic changes in the economy of the area.