The institution discovered in 2014 that the astronomical treatise ‘Sidereus Nuncius’ had been replaced by a copy but did not report the crime until 2018
For four years, Spain’s National Library concealed the fact that one of the most important works in its extensive collection had been stolen: Sidereus Nuncius, or Sidereal Messenger, an astronomical treatise published by Italian astronomer Galileo Galilei in 1610. The National Police’s historical patrimony department has been investigating the work’s disappearance since 2018. According to specialists who spoke to EL PAÍS, the Latin treatise is worth around €800,000. In the work, Galileo describes the astronomical discoveries he made after building and perfecting a telescope in 1609, including that the moon is mountainous, that Jupiter has four moons and that the Milky Way is made up of separate stars.
It took the National Library four years and four months to report the theft – even though the technical department had known that the original had been replaced by a copy since May 2014, when book restorers discovered it by accident during a program to preserve old books from acid-deterioration called IFADU. But despite this discovery, in these four intervening years, the forged copy of Sidereus Nuncius left by the thief continued to appear in the library’s catalog as the original, according to an investigation by EL PAÍS.
This was not the first time that the Sidereus Nuncius had been stolen from the National Library. The important work, along with 100 other books by astronomers such as Johannes Kepler and Nicolaus Copernicus, were taken from the library in 1987, and recovered two years later by police. As there was nothing different about the treatise, the returned work was thought to be the original.
