The library is one of the most impressive places of the Seminary. It holds more than 8,500 books dated from the 16th century to the 18th century.
One of the oldest books is from 1507, by St. Alberto Magno. There are 27 antiphonaries that belong to the Cathedral Chapter but were given to the Seminary's guard.
The back of the library is composed of works about Sacred Scripture, Canon and Civil Law, Theology and Dogmatic, Patristics, Liturgy, Philosophy and Humanities. It is also worth mentioning that the library's collection includes a work that contains erotic content.
Today, the library is located where the first refectory used to be. The refectory was turned into a library by the founding Bishop, who kindly donated his private collection to the Seminary in the first years of its existence.
Sadly, the Seminary experienced an unfortunate event: the disappearance of one of the rarest books in the world, written by Aires de Barbosa, a well-known Portuguese humanist. Out of the four versions of the original book (Salamanca 1516), only the one in Amsterdam and the one in the Major Seminary of Coimbra are complete. The other versions, like the one in the University of Coimbra, are incomplete.