LIBRO, an acronym for "The Library of Iberian Resources Online", is a unique collection of secondary sources about Medieval Spain (defined as the fourth through seventeenth centuries), created in 1999 by the American Academy of Research Historians of Medieval Spain.
"Secondary" here means fairly recent history books about the period. "Primary" means usually eyewitness sources--or as close as possible in time to the original event. In medieval terms, all medieval-era sources are considered primary.
There are a lot of books online, not least the famous Gutenberg Project. However, all of those that legally appear on the Web have seen their copyrights expire and have entered Public Domain. Usually, this cannot happen until at least 70 years after the death of the author. This makes any history books online, unless they contain significant primary source material, not very useful to an academic historian. Historical research can progress quickly within a single decade, let alone seven.
However, LIBRO has found a way around this. Most academic books remain in print only for a few years with a single publisher. Then, the copyright reverts to the author. Only a few ("bestsellers" like Malcolm Barber's general history of the Templars, "The New Knighthood") see a second printing, let alone republication in paperback, which extends the book's exposure and marketability. In the LIBRO project, significant authors in the field have agreed to let LIBRO post their books online once they have gone out of print.
There are limitations, of course. All of the books on LIBRO are in English, even though much of the most original work in Spain is in Spanish, Portuguese or Catalan. The earliest book was published in 1906 (Henry Lea's History of the Spanish Inquisition), the latest in 1998. The list is certainly not comprehensive, but it does provide the academic with a number of otherwise expensive and/or difficult to find sources. It also gives the casual reader a good collection to start off in delving into the academic historiography of Medieval Spain. For example, one major history of this week's article subject, Queen Urraca of Castile and Léon, "The Kingdom of León-Castilla
under Queen Urraca, 1109-1126" by Bernard F. Reilly, is found on LIBRO.
LIBRO is one of those collections that are helpful to both academic and popular historians. While films like El Cid (this week's film review) are great fun, we don't need them to fill in our history--not in the age of the World Wide Web, when real history is out there, waiting to be found and read.