The Archivio Storico della Pontificia Università Gregoriana contains the unpublished collection Epistolae Bellarmini Cardinalis, which is composed of about 2674 letters either sent to Cardinal Robert Bellarmine, or written by him, between March 1599 (when he was appointed as Cardinal) and October 1621. The letters in the collections are typewritten, and were collected by François Xavier Le Bachelet S.J. (1855-1925) and Sebastiaan Peter Cornelis Tromp S.J. (1889-1975). They are divided into nine volumes in chronological order: the first eight volumes contain the so-called Collectio Le Bachelet, while the last volume was added later by Tromp. For more information see Collection Epistolae Bellarmini Cardinals.