These manuscripts were found in the mid-1920s by the Icelandic philologist Jón Helgason in the Arnamagnæan Collection at the University of Copenhagen. He copied the glossaries, translated the Icelandic words into German and sent the copies to professor C.C. Uhlenbeck at Leiden University in the Netherlands. Uhlenbeck had expertise in Basque, but since he retired from the university in 1926, he gave the glossaries to his post-graduate student Nicolaas Gerard Hendrik Deen. Deen consulted with the Basque scholar Julio de Urquijo, and in 1937, Deen published his doctoral thesis on the Basque–Icelandic glossaries. It was called "Glossaria duo vasco-islandica" and written in Latin, though most of the phrases of the glossaries were also translated into German and Spanish.