From the eleventh to the thirteenth centuries, the Iberian Peninsula was immersed in armed conflicts. The Christian monarchs were trying to regain territory from the Islamic kingdoms using different strategies. In the eleventh century, the border between the Christian and Muslim kingdoms was situated on the line of the River Douro. To the south of this geographical limit was an unpopulated no-man’s-land for a long period of time. The new or repopulated towns in this area were repeatedly attacked during the tenth century by the Moors, which forced the population to flee. It was an unstable area, where the towns had little protection and were not safe, and where the control over the territory was not assured.
The phenomenon of the “Comunidades de Villa y Tierra” took place in this border area, the south of the Leon and Castile kingdoms, which extends from the river Douro to the river Tagus. Its principal objective was to colonize the area to guarantee a territorial and political control thereof. This means of repopulation was organized in regions, geographically extense communities that had a principal town, the "Villa" and a subordinate territory, the "Tierra", dotted with small villages. The "Villa" were favoured from the legal point of view, as they possessed highly advantageous charters that had been written with the aim of attracting population to a deserted and unsafe territory. In this context, a new, little seen social organization arose in the medieval world; one in which the people had greater liberty and could participate in the city’s government through assemblies.
The towns that formed the nucleus of each council were strongly protected by perimeter walls. The villages, on the other hand, had no walls, but the people could go to the town at times of danger, even with their livestock. The town walls were usually extense, covering a large surface area that enclosed not only the urban buildings, but also areas dedicated to pasture and cultivation.
This study relates the constructive techniques of the walls of towns in the area that was under the control of the Diocese of Segovia, which includes Coca, Cuéllar, Fuentidueña, Maderuelo, Pedraza y Sepúlveda. Many of these towns have remains of defensive architecture, and a comparison between constructive techniques is possible. The analyses of the remains depend on their condition, in some cases they are abandoned, in other cases a restoration or a reconstruction has been carried out. Over the last few centuries, the town walls in Spain have mostly been demolished. Nowadays, the situation has changed, though cases of abandonment and destruction still occur due to a scarcity of economic resources or a lack of interest. Of the towns under study here, there are a few cases of ruined walls, such as Fuentidueña (Segovia), where the walls still survive over a great part of their circumference, but in a state of progressive deterioration. In other cases, only some parts of the wall are abandoned or deteriorated. Some of these constructions have recently been restored, or partly reconstructed.
The formwork technique of gravel or stone cemented with lime is present in all the cases studied. In some it is the main system used while in others, there are other, equally important techniques being used. It consists of large rectangular blocks, locked together as if they were bricks, of about 290-290cm long and 105-130cm high, and a depth corresponding to the thickness of the wall, of about 200cm. The use of formwork using gravel cemented with lime is very common in the Iberian Peninsula, with variations in both materials and form at the time of execution.
The marks left by the formwork are visible in the walls studied. In the sections that have survived, the mark of the horizontal timbers used is visible, and the timber itself is even conserved in many cases inside the wall. The methodology used in this work is the observation and the study of the remains that exist, creating elevations using orthophotography and taking measurements of the constructive elements that are still visible.
One of the conclusions of this study is the use of formwork in all the christian walls of the research. This system was used in all of them and, although it is found in defensive architecture in other parts of the Iberian Peninsula, it is interesting that it is also found in the walls of these towns, together with other common elements. Although there are differences in the dimensions of the formwork, they are still very similar, with relatively constant dimensions.
Finally, the divulgation of the constructive techniques of these walls is a key aspect for its conservation. The lack of knowledge about the medieval way of building walls has led in many cases to its destruction or to unfortunate restorations. With this research, it is intended to contribute to the understanding of these constructions for appropiate recognition as well as to encourage proper restorations.