In September 1807, early in the Anglo-Danish War of 1807–14, the British fleet bombarded the city of Copenhagen. Among the buildings struck was the Church of the Holy Trinity, which housed in its attic the University Library of Copenhagen. Some grenades fell through the roof, and this book belonging to the library was among those that were hit. Shown here are the bombed book and the grenade. The book is the first printed edition of, ironically, Defensor pacis (The defender of peace), a major work of medieval political philosophy by the Italian Marsilius of Padua (1275/80–1342/43). Marsilius supported the Holy Roman Emperor, Ludwig IV, in his power struggle with Pope John XXII, and in this treatise Marsilius argues against the proposition that the popes had inherited unlimited power from the Apostle Peter. Instead, Marsilius maintains that the originator of law is the people, who may, however, delegate power to representatives. The book was printed in Basel, Switzerland in 1522.