Two antique books dating back to the 17th century, stolen in Stockholm in the 1990s and sold to Americans by a German auction house, were returned to Sweden on Wednesday. US authorities handed back the books, intercepted by the FBI from a rare book store in Manhattan and from Cornell University, to the National Library of Sweden at a ceremony in New York. Both books were printed in the early 1600s in Europe. Neither of their most recent owners knew they had been stolen. The work by Italian architect Nicola Sabbatini, printed in 1638, is about stage craft and theater machinery, and ‘Oculus’ by Bavarian physicist Christopher Scheiner is about the history of optics. It was printed in 1619. US prosecutors said they are two of at least 56 rare books stolen from the National Library of Sweden by employee Anders Burius between 1995 and 2004.

Read More: United States returns 17th century books, stolen in Stockholm in the 1990s, to Sweden