 Bernard Bolzano (1781–1848) was a Catholic priest, a professor of the doctrine of Catholic religion at the Philosophical Faculty of the University of Prague, an outstanding mathematician and one of the greatest logicians or even (as some would have it) the greatest logician who lived in the long stretch of time between Leibniz and Frege. As far as logic is concerned, Bolzano anticipated almost exactly 100 years before Tarski and Carnap their semantic definitions of logical truth and logical consequence; and in mathematics he is not only known for his famous Paradoxes of the Infinite, but also for certain results that have become and still are standard in textbooks of mathematics such as the Bolzano-Weierstrass theorem. Bolzano also made important contributions to other fields of knowledge in and outside of philosophy. Due to the versatility of his talents and the various fields to which he made substantial contributions he became one of the last great polymaths in the history of ideas.