Complex sentence: Abraham Geiger, who had been active in establishing Reform Judaism wanted a University for Jewish Studies in Berlin, unable to become part of the University of Berlin, he was involved in 1870 in creating a separate institution.
Split into simpler sentences: Abraham Geiger, who had been active in establishing Reform Judaism, wanted a university for Jewish Studies in Berlin. Unable to become part of the University of Berlin, he was involved in 1870 in creating a separate institution.