A 13th-century letter from Genghis Khan’s grandson demanding homage from the pope is among a collection of documents from the Vatican’s In a letter dated 1246 from Grand Khan Guyuk to Pope Innocent IV, Genghis Khan’s grandson demands that the Pontiff travel to central Asia in person. Although scholars have had access to the secret archives since 1881, they remain closed to the general public. The Holy See’s archives contain scrolls, parchments and leather-bound volumes with correspondence dating back more than 1,000 years. High-quality reproductions of 105 documents, 19 of which have never been seen before in public, have now been published in a book. The Vatican Secret Archives features a papal letter to Hitler, an entreaty to Rome written on birch bark by a tribe of North American Indians, and a plea from Mary Queen of Scots.