Police returned precious maps, including some cut out of 15th and 16th century books by Greek astronomer Claudius Ptolomy, to Spain's National Library. Police tracked stolen maps to locations on three continents.
Ten of 15 rare, hand-penned maps stolen from the main reading room of the library were handed over to the Culture Ministry by Interior Minister Alfredo Perez Rubalcaba, who received them from the police and Interpol.
Spanish researcher Cesar Gomez Rivero is accused of cutting the maps out of manuscript books and selling them over a period of several years. He is in custody in Argentina, where he is being investigated, but he has not yet been brought to trial.
Rubalcaba did not announce any additional arrests.
Some of the maps came from Ptolomy's 1482 book "Cosmographia" and "Geographia" (1507).
World maps by Ptolomy were used by travelers for hundreds of years. Christopher Columbus is believed to have sailed with Ptolomy's maps when he discovered America in 1492.
Eight maps were recovered from Buenos Aires, Argentina. Two others were found in New York and handed over to Spain's police chief in Washington, D.C., on Thursday. Another is awaiting authorization to be returned from Sydney, Australia. At least four that date to between the 15th and 17th centuries are still missing, Rubalcaba said.
The theft led to the resignation in August of the library's director, Rosa Regas.
The new director, Milagros del Corral, said a major audit would take place at the former royal library, founded in 1712, in January.
"I can't discount that we'll find more unpleasant surprises," Del Corral said at a news conference. The last audit took place in 1988, Del Corral said.
Up until the mid-1980s some of the oldest references available to researchers in the main reading room were not even alphabetically archived.
The library was hit by scandal in 1967 when Leonardo da Vinci's Codexes Madrid I and II were accidentally found after having been considered lost for 200 years.
The library houses 28 Leonardo codexes.