A book collection significant in the history of Latvian culture – the library of the Riga Jesuit College (1583–1621) – was relocated to Sweden when Swedish troops occupied Riga in 1621 and today forms one of the oldest book collections in the Uppsala University Library. While the College existed, the books of Livonian priests and Medieval books and manuscripts from the St Mary Magdalene Cistercian monastery also came into its collection. Valuable specimens include the Catechismus Catholicorum. Iscige pammacischen (St Peter Canisius' Catholic Catechism) – the oldest surviving text printed in Latvian, printed in Vilnius in 1585. Mention should also be made of a copy of the Catholic Agenda issued in Leipzig in 1507, which contains the so-called Gisbert Lord's Prayer – the oldest handwritten text in Latvian.
Today, copies from the former Riga Jesuit College library are scattered among both Swedish libraries and in the repositories of the national libraries of other European countries. Two books have survived in the Academic Library of the University of Latvia. The collection of the Vilnius Church Heritage Museum also includes church paraphernalia belonging to the Riga College, which will be displayed as part of the digital exhibition.
The Swedish bibliographer Isak Collijn (1875–1949), who studied the Riga Collection while working at the Uppsala University Library, made a great contribution to the reconstruction of the Riga Jesuit College library. He compiled a card index comprising bibliographic information on Riga Jesuit College collection copies identified in the Uppsala University Library and other Swedish repositories of early printed items. Isak Collijn dedicated many years to research into the Riga Collection, however, his work remains unfinished and unpublished. The said card index is an indispensable reference source in the identification of the copies from the former Riga Jesuit library, consequently it was digitised and also utilised as the basis for the bibliographic reconstruction undertaken by the NLL.