The Bibliotheca Palatina ("Palatinate library") of Heidelberg was the most important library of the German Renaissance, numbering approximately 5,000 printed books and 3,524 manuscripts. 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.
In the 1430s, Elector Louis III founded the Stiftsbibliothek in the Heiliggeistkirche, which had good light for reading. This library formed the core of the Palatine Collection established by Elector Ottheinrich in the 1550s, together with the University Library Heidelberg. Essential manuscripts from the original Bibliotheca Palatina include the Carolingian "Lorsch Evangelary", the Falkenbuch (De arte venandi cum avibus, cpl 1071, commissioned by Frederick II), and the Codex Manesse (cpg 848)
Further important manuscripts were acquired from the collection of Ulrich Fugger (d. 1584), notably the illustrated Sachsenspiegel (cpg 164). Joseph Scaliger considered this Fugger Library superior to that owned by the Pope; the manuscripts alone were valued at 80,000 crowns, a very considerable sum in the 16th century.
The Palatinate suffered heavily in the Thirty Years War, and in 1622 Heidelberg was sacked by the Catholic League, whose general Count von Tilly was in the employ of Maximilian of Bavaria. Although many books were torn or "dispersed among private hands" during the sack, Maximilian found it prudent to confiscate the remaining manuscripts and present them to Pope Gregory XV as "a sign of his loyalty and esteem." It was a prominent prize captured during the Thirty Years' War. The Catholic forces who occupied Heidelberg competed for ownership, but Pope Gregory XV succeeded in having the collection transported to Rome. The preparations to secure transport the collection to Rome were supervised by the Greek scholar Leo Allatius, sent to Heidelberg by the Vatican.