Otto Toeplitz:

Otto Toeplitz was a professor at the University of Bonn and dedicated himself to studying the history of mathematics. Among other things, he is famous for the eponymous Toeplitz matrices, where the values are arranged in a specific structure. Photo: Toeplitz: Oberwolfach Photo Collection, archives of P. Roquette, Heidelberg, CC BY-SA 2.0 DE, via Wikimedia Commons