The School preferred historical, political, and social studies to self-referential mathematical modelling. Most members of the school were also Kathedersozialisten, i.e. concerned with social reform and improved conditions for the common man during a period of heavy industrialization. The Historical School can be divided into three tendencies: the Older, led by Wilhelm Roscher, Karl Knies, and Bruno Hildebrand; the Younger, led by Gustav von Schmoller, and also including Étienne Laspeyres, Karl Bücher, Adolph Wagner, and to some extent Lujo Brentano; the Youngest, led by Werner Sombart and including, to a very large extent, Max Weber.