Metamorphosis of puerta tierra from Cadiz (Spain) in the 18th Century as a paradigm of modern fortification

Abstract

The city of Cadiz, located in a peninsula, was initially defended by its only land access through a wall of land extended from coast to coast across the isthmus; this access was erected at the beginning of the 16th century. After being devastated by an Anglo-Dutch attack in 1596 (where they had access by this flank), Felipe II decided to rebuild the city and this defensive element. Furthermore, after the Spanish War of Succession, Puerta Tierra [Land Gate] experienced a considerable metamorphosis that would complete its integration in the first quarter of the 18th century, becoming now a complete defensive system that would protect one of the most important squares of the Kingdom of Spain. In this sense, this work can be considered one of the most representative examples of the application of military treatises based on the ideas developed by the French marshal Vauban and applied by the Spanish engineer Ignacio Sala. This research focuses on the defensive elements whose works, which were developed between approximately 1730 and 1760, involved large earthworks and an intensive use of the oyster stones, resulting in the final configuration of the work. The analysis developed below is based on the plans prepared by the Spanish engineers involved in this construction.