Many times when we visit monuments such as the Castles of Old San Juan, we do not consider just how much work it takes to construct them. First, people had to make a study of what is to be protected, then formulate a plan of construction, then assemble the necessary labor force. In the 16^th century, when the construction of El Morro began, the Spanish government sent Field Marshall Juan de Tejeda and Military Engineer Juan Bautista Antonelli to Puerto Rico to make such a study. Before building could begin, workers were needed to open quarries, cut and remove the stone which was to be the basic component of San Juan’s fortifications. Then, men had to cut and carry the ausubo trees for carpenters to make into floors and doors. Bricklayers were needed for the walls and men had to work in the foundry, making iron locks and door knockers. Bricks had to be made and sand and lime brought for the construction work. Housing was built for the workers, along with kitchens to feed them and, of course, the supervisors, who directed every aspect of the work.

In designing the fortifications they had to take into account the potential enemies who may attack, the powerful weapons in use at the time, and any natural feature which may be taken advantage of. The drawing shows various components of a good fortification which were included in the construction of the forts of Old San Juan. The men who had the task of designing and supervising the construction of the fortifications were well versed in the most advanced defense strategies of their time, and had the ability to overcome any problems which arose.

For example: San Juan was an island without lakes or rivers of drinkable water. How could the water necessary for the soldiers’ survival be provided?

Solution: Build cisterns below the main squares of the forts and create a system of channels to collect rainwater, thus storing a large quantity of water which could be used for drinking, cooking, cleaning and washing.