It is Rome, September 11, 1683. The citizens of the city wait anxiously for the news of the outcome of the battle of Vienna in which the Islamic forces of the Ottoman Empire are laying seige to the defenders of Catholic Europe. Meanwhile, a suspected outbreak of plague causes a famous Roman tavern to be placed under quarantine. Among those detained in the Locanda Donzello is the mysterious Atto Melani, a spy in the service of the French king. With the help of the young serving boy, he discovers a secret passage leading deep into the catacombs. Their nocturnal journeys into the Roman underworld lead them to some startling discoveries, including a plot to assassinate Pope Innocent XI, an alliance between the papacy and the Protestant hero William of Orange, and plans to use the plague as a weapon of mass destruction in the battle between Islam and the West.Meticulously researched and brilliantly conceived, Imprimatur contains startling revelations that have been concealed for centuries. It is a captivating thriller that sheds new light on the power struggles of 17th century Europe and events whose repercussions are still felt today.