MEXICO CITY (REUTERS) - Mexico's foreign ministry said on Thursday (Sept 23) it had recovered valuable manuscripts from the 16th century, including some relating to conquistador Hernan Cortes, months after a group of academics reported them missing from Mexico's national archives.

In apparently systematic fashion, 10 documents were stolen over several years from a collection dedicated to Cortes and later put up for sale in international auction houses including Swann, Bonhams and Christie's, the academic investigators said.

Mexican Foreign Minister Marcelo Ebrard said on Twitter that the documents had been recovered by US investigators and the office of the attorney general of New York.

"Today the documents were handed over to the foreign ministry and taken into the custody of our consulate to be transported to Mexico City," Ebrard wrote, after noting that the documents had been sold illegally.

Among the recovered manuscripts is a document from 1521 that reveals political intrigue involving Cortes, who led the Spanish army that with its local allies overthrew the Aztec Empire.

Documents relating to Cortes are highly sought after, and nine other such papers were sold in US galleries, fetching tens of thousands of dollars, the academics said.

The investigating team found the manuscripts by matching images posted on the internet by auction houses with images from the investigation at the National Archives of Mexico.

The academic sleuths who tracked down the documents comprised Michel Oujdik and Sebastian van Doesburg at the National Autonomous University of Mexico, Rodrigo Martinez at the National Institute of Anthropology (INAH) and Maria del Carmen Martinez at the University of Valladolid, Spain.