The Royal Letters Patent that he granted, the predecessor of the current legal deposit requirement, made it mandatory for printers to submit a copy of every book printed in Spain to the library.

A year later, women were allowed access to the library for the first time, after a petition from writer Antonia Gutiérrez was granted by Queen Regent Maria Christina.

On 16 March 1896, the National Library opened to the public in the same building in which it is currently housed and included a vast Reading Room on the main floor designed to hold 320 readers.

During the Spanish Civil War close to 500,000 volumes were collected by a Confiscation Committee and stored in the National Library to safeguard works of art and books held until then in religious establishments, palaces and private houses.

As the country's national library, it is the centre responsible for identifying, preserving, conserving, and disseminating information about Spain's documentary heritage, and it aspires to be an essential point of reference for research into Spanish culture.