The group of mills formed by the Santibañez tide mill (according to the time and the source that is consulted, it has also been called the Arrierillo, La Roqueta, Larraque or La Merced) is considered to have had the adjacent esplanade fortified at the beginning of the 19th century. Here, they located barracks for troop accommodation and a pier. Other buildings also appeared at the beginning of the nineteenth century, which are located very close to this nucleus: a guard and a warehouse of gunpowder and spare parts.

It formed part of the Third Line of the defences established during the siege of the cities of Cadiz and San Fernando (known as Isla de León at that time) between February 1810 and August 1812 by the Napoleonic armies. Its position is specially protected as it is at the bottom of the bay, further away from the French positions of the Trocadero (and therefore out of reach). At the same time, its position dominates the Santibañez inlet, and there is also a well just a few metres away. During that time for all these reasons, it constituted a magnificent station for the fine forces, which used it as a provisions point for those who travelled through the interior of the Bay to the Punta Cantera station. To do this, they fortified it and equipped it with artillery, in the adjacent esplanade that is conditioned for that purpose.

Previously, the artillery was used in the capture of the French Admiral Rosilly’s squadron in June 1808, although due to its remoteness it would only have a merely dissuasive role.

In 1820, this time during the Constitutionalist uprising against the absolutist government of Ferdinand VII, the mill, along with other enclaves of the Bay, was again used militarily by the rebels, through the installation of an artillery battery.