Complex sentence: Gothein was the author of valuable works on cultural and economic history, primarily of the 15th to 17th centuries and was one of the founding fathers of the University of Mannheim's predecessor, the "Handelshochschule Mannheim".
Split into simpler sentences: Gothein was the author of valuable works on cultural and economic history, primarily of the 15th to 17th centuries. Furthermore, he was one of the founding fathers of the University of Mannheim's predecessor, the "Handelshochschule Mannheim".