Jean-Guillaume de Neubourg-Wittelsbach
At the end of the century, Hartsoeker had become quite famous. In 1699 he was elected member of the French Academy of Sciences and in 1704 of the Prussian Academy of Sciences, in both cases as one of the first foreign members. Czar Peter met him in Amsterdam and offered him the chair of mathematics in St Petersburg. Hartsoeker did not accept, but the czar did finance an observatory for him in Amsterdam. Later, in 1704, Hartsoeker accepted the offer of Johann Wilhelm, Elector Palatine to become "first mathematician and honorary professor of philosophy" at the University of Heidelberg. The last years of his life were spent in Utrecht.