The Library of Congress has an historical link directly to the old Library of the Courts, established in 1811 by the Cadiz Cortes. It has been the library of the lower Chamber during periods of the two-chamber system, and library of the Cortes when only one Chamber existed.
Along its history during these nearly two centuries, four clearly defined periods can be distinguished:

1811 to 1838: Library of the Cortes
This was the period of greatest drive and splendour in the entire history of the Library, thanks to the ambitious conception of the Cortes and of its first librarian, Bartolome Jose Gallardo, who directed the entity as if it were the national library. This is the most documented phase in the library's history, and the period that provided the greatest amount of literary riches as far as holdings are concerned.

1841 to 1936
This phase, in which the library received various designations according to changes in the Chamber, was a stable period with a development less spectacular than before, but more effective from the point of view of the librarian. From 1850, the Congress arranged for its own specific headquarters in the current palace and then provided buildings for the Library. During this epoch, specifically between 1857 and 1928, ten general or partial catalogues were published, and information began to appear in different publications of the Chamber about the new holdings donated to the Library.

1943-1977: Library of the Spanish Cortes
The scarce functioning of the Chamber provokes a certain level of inactivity that begins to decrease at the end of the period.

1977 to present: Library of Congress
In 1977 the process of development begins with other libraries of representative institutions. The creation of the civil servants Body of Archivist Librarians of Parliament in 1978, the slow but uninterrupted increase in personnel and materials, the policy of holdings acquisition and, finally, the process of creating an information system, have been decisive factors in determining the growing importance of the Library within the document services of the Chamber.