According to researchers Kent Henderson and Tony Pope, it is estimated that some 10,000 Spanish citizens were executed solely for their purported Masonic membership under Franco's rule.
When General Francisco Franco established his fascist dictatorship in 1939 after the end of the Spanish Civil War, the fraternity was among the first institutions to be suppressed. Because of the chaotic competition among the Masonic bodies, Spanish Masons were in no condition to resist this new era of persecution. Lodges that had operated openly and were easily identifiable were literally obliterated.
Franco stayed in power for four decades, and he frequently railed against "the Jewish-Masonic conspiracy" right up until his death in 1975. Only then could Masonry slowly begin to rebuild itself again in Spain. But precious few traces of the earlier days of the Craft there survive today. One has just reemerged in Barcelona.
From an article on the Atlas Obscura website today:
During the 19th century, the fraternal order of Freemasons had lodges in practically every European-influenced country. Spain was no different, though the traces of the Freemasons are mostly hidden now—apart from this once-secret library.
Barcelona, much like London, Paris, Buenos Aires, or Washington D.C., has an extraordinary artistic and architectural heritage based in Freemasonry. Masonic symbols like pyramids and the all-seeing eye can be found in cemeteries, libraries, sculptures, even government buildings. Passeig Sant Joan ("Saint John Avenue") is devoted to Saint John, the chosen patron of Christian Freemasons. Ildefons Cerda, the urban planner who designed Barcelona's layout, was a member, and imagined a utopian city based on Masonic principles. At the turn of the century, there were nearly 170 Freemason lodges in Spain alone.
Rossend Arús was an influential journalist and playwright of the 1800s who used his Freemason associations for republican political favor. Along with his fellow Masons, Arús had control of the city from behind the scenes. He began to host meetings in his home in 1888, and it soon became an official Masonic Temple. After his death in 1891, the house was turned into library dedicated to Freemasonry.
During Franco's regime, almost every Freemason building was torn down and the Masons were prohibited from meeting. Like many fascist leaders, Franco feared uprising from independent organizations, as well as having misplaced antisemitic beliefs about the Freemasons' purposes. Some in power sympathized with the Freemasons though, and the Rossend Arús library was shut down and hidden from view during the Franco years. After the dictator's death and the end of his regime, Freemasonry slowly but surely crept its way back into Spain.
After timidly growing less and less private and secretive, the Freemasons of Barcelona have opened Biblioteca Publica Rossend Arús to the public in Passeig Sant Joan. The luxurious reading rooms, golden frames, and precious marble of the 19th century still impress visitors. The collection includes important Masonic texts, as well as anarchist collections and rare magazines and literature. The third original version of the Statue of Liberty also resides in the main entrance. Today, the Rossend Arús is the best library for studying the working class history and Freemasonry in Catalonia. Public hours: 3-7PMAfter Franco's death, it took another four years before the courts declared anti-Masonic laws to be unconstitutional. Masonry returned, largely with the assistance of the three largest French grand lodges, and as a result, there are again competing Masonic bodies at work there today.
The Grand Lodge of Spain was formed in 1982 in Madrid, and is the obedience that is recognized by the U.S., UGLE, and the bulk of the regular Masonic world. They currently have 2,500 members and 179 lodges.