Historia Eustachio Mariana
Historia Eustachio Mariana is a 1665 work by the Jesuit scholar Athanasius Kircher. It describes his chance discovery of a ruined shrine of the Virgin Mary at Mentorella in Tivoli, the site where tradition held that the Roman martyr Saint Eustace had experienced conversion to Christianity. The book was dedicated to Giovanni Nicola, abbot of the monastery at Vulturalla, and a member of the family of the counts of Poli. It was intended to help raise funds for the restoration of the chapel, and it was Kircher's first topographical work.: 20
Following the book's publication, Kircher secured funds from (among others) Leopold I, Holy Roman Emperor, Maximilian II Emanuel, Elector of Bavaria and Pedro Antonio de Aragón. He rebuilt and restored the chapel, while adding a set of large speaking trumpets to broadcast calls to attend Mass.
The book popularized the false claim that the shrine had been built by Constantine the Great and consecrated by Pope Sylvester I. This was largely based on Kircher's fanciful speculations.