## 6 Frankfurt

Frankfurt University, founded in 1914, employed numerous Jewish scientists during the Weimar Republic. This was also true for the mathematical institute. All Jewish professors and researchers – and therefore nearly the entire institute – were removed from their positions in1933. Not all of them were able to escape from Germany in time.

A unique achievement in Frankfurt between 1925 and 1931 was the History of Mathematics Seminar, in which most Frankfurt mathematicians met regularly with advanced students to discuss ancient and early modern mathematical texts. The list of topics discussed in this seminar reads like an attempt to counter Oswald Spengler and other cultural critics by demonstrating the continuous development of mathematics through a detailed study of sources.

For its founder Max Dehn (1878–1952) the history of mathematics was connected with more general issues of human culture. Following his forced retirement in 1935, Dehn wrote several challenging studies on ancient mathematics, in which he explored the connection between mathematics and philosophical thinking. Among these are “Raum, Zeit und Zahl bei Aristoteles, vom mathematischen Standpunkt aus” [Space, time and number in Aristotle from a mathematical perspective], which was published in 1936.