Abstract

Due to lacking reliable sources almost no details were available on the educational journey of the joung Descartes. Moreover, contradictions in several publications resulted in the doubt, whether these events, which are so important for the history of science, ever hapened at all. Folowing careful and comprehensive research at the City Archives Ulm, the Hessian City Archives Darmstadt and the Bavarian State Library in Munich the author found evidence that René Descartes met the mathematician and master fortress builder Johann Faulhaber in Ulm.1 Now, the first summary of Descartes' travel report can be given based on further findings (in reliable sources) and corroborated by numerous facts.