What about the ancient Museum Bollandianum?
The library gathered by Rosweyde, Bolland and their successors in Antwerp was dispersed after the suppression of the Society of Jesus. Most medieval manuscripts were sent to the Royal Library in Brussels but some were lost. The Collectanea Bollandiana, the manuscript materials gathered in view of the publication of the Acta Sanctorum, can be found in part at the Royal Library, in part in today’s Bollandist Library. The printed books were mostly auctioned but a number of volumes can still be found in today’s Bollandist library.
For more informations: Fr. DOLBEAU, Les sources manuscrites des Acta Sanctorum et leur collecte (XVIIe-XVIIIe siècles), in De Rosweyde aux Acta Sanctorum. La recherche hagiographique des Bollandistes à travers quatre siècles. Actes du Colloque international (Bruxelles, 5 octobre 2007). Ed. R. GODDING e. a., Bruxelles, 2009, 105-147 ; B. OP DE BEECK, La bibliothèque des Bollandistes à la fin de l’ancien régime, ibid., 149-284.