In 1436 Elector Louis III, Count Palatine of the Rhine, founded the Stiftsbibliothek in the Heidelberg Heiliggeistkirche, a church which has good light for reading. This was the origin of the Bibliotheca Palatina. The Bibliotheca Palatina ("Palatinate library") of Heidelberg "became the most important library of the German Renaissance, numbering approximately 5,000 printed books and 3,524 manuscripts. The Bibliotheca was a prominent prize captured during the Thirty Years' War, taken as booty by Maximilian of Bavaria, and given to the Pope in a symbolic and political gesture. While some of the books and manuscripts are now held by the University of Heidelberg, the bulk of the original collection is now an integral part of the Bibliotheca Apostolica Vaticana at the Vatican" (Wikipedia).