Pigafetta was an eye-witness to the siege of Paris, then under the dominion of the League, by Henri IV in 1591. His detailed account is dedicated to Pope Gregory XIV. The book is accompanied by a plan of Paris and its environs, facing west, designed to show the city's defenses against the attackers. Three defensive chains are supported by boats in the river Seine. Temporary fortifications, concentric to Philip Augustus's wall, are shown. From the heights of Montmartre and Montfaucon, across the river, the attackers are cannonading the city. In the east (bottom of the plan), the king's army is on the march; to the left is the circular camp of the Duke of Parma, through whose intervention the attack was repulsed. The town of Corbeil, on the Seine, is under heavy assault.