The bastioned system of the Spanish city of Badajoz consists of a military fortification formed by a set of defensive walls, city gates, bridges, forts, towers, bastions, hornworks, moats, tunnels, and ravelins, among other defensive elements. It was built during the 17th and 18th centuries, following the defensive construction theories popularized by the French military engineer Marquis de Vauban, as an extension of a previous defensive enclosure that protected the Portugal–Spain border city.

From its founding by Ibn Marwan—over an earlier Visigothic settlement, as Badajoz has been inhabited since prehistoric times—the city maintained a stronghold character up to the 20th century. Its strategic location at the crossroads of two major routes: one from Castile to Andalusia, and the other to Lisbon, along with its status as a border city with Portugal, has led to both advantages for Badajoz's development and numerous conflicts involving various armies over the centuries. Consequently, the city has been protected by several defensive enclosures.

The first fortifications were carried out by Ibn Marwan, who ordered the erection of mortar walls. This was followed by restoration work undertaken by Abd Allah Ibn Muhammad Ibn Abd al-Rahman, the founder's grandson, in 913 and by Abdallah ibn Al-Aftas, the first Aftasid king of the Taifa of Badajoz, in 1030. In 1169, the Alcazaba was built, closely resembling the present structure, with some elements dating back to the Almohad period. The final Muslim restoration was commissioned by Abu Yahya Ibn Abi Sinan at the beginning of the 13th century.

After the conflicts between Castile and Portugal in the 14th century, relations between the two regions were normalized, leading to a period of peace that lasted nearly two and a half centuries. However, in 1640, when Portugal gained independence from the Spanish Monarchy, Badajoz became a border city. Due to its strategic importance, the Castilian authorities recognized the need to enhance its defenses. Consequently, both the Crown and the authorities of Badajoz decided to undertake significant fortification works. Despite the various options proposed by military engineers, the decision was made to implement the Vauban system. The fortification efforts were marked by improvisation amid economic difficulties, and the reforms and improvements were made incrementally to the existing defenses.

Background

The city of Badajoz, specifically the oldest area, located in the highest part of the promontory called Cerro de la Muela, was protected by an enclosure built during the Islamic period, with its fortress known as the Alcazaba. During Islamic times, Badajoz was encircled by a defensive wall that safeguarded the al-qasbah (ksar), the citadel, which served as the administrative center and residence of the rulers of the Kingdom of Badajoz—one of the largest taifas of the Iberian Peninsula. This area housed the Alcázar, the mosque, and one of the era's largest libraries. The defensive wall underwent several extensions over time. The buildings within the enclosure reflect its varied functions across different periods: as an Islamic citadel with various extensions in the 9th–13th centuries until it resembled the so-called Cerca Vieja (Old Wall); as a Christian late medieval castle featuring the first Badajoz Cathedral, built on the site of the former mosque and various "fortified houses" for defense (13th–16th centuries); and as part of the modern fortifications (17th–19th centuries), which included different religious buildings, secret passage, and cisterns reused over time.

The city of Badajoz continued to expand beyond its original walls, particularly to the west and south, where the terrain was flatter. This expansion was encircled by a medieval wall of rammed earth, likely of Almohad origin, with subsequent extensions. By the end of the 15th century, a late medieval pentagonal wall, contemporary with the Catholic Monarchs, was constructed. This wall connected with the Palmas Gate near the Palmas Bridge and the Pajaritos Gate, both dating from the 16th century. Inside these walls were the neighborhoods forming the historic district. However, these defenses proved insufficient against the advancing artillery technology of the following century. In 1642, during the conflict with Portugal, a series of isolated and improvised defensive structures were initiated, starting with the fort of San Cristobal. Located on the right bank of the Guadiana River, north of the city, on a significant promontory known as Orinaza Hill, this fort was considered the first of its kind for defensive fortifications. It protected the bridgehead, a crucial strategic element, as the bridge served as the main entrance to Badajoz. Defensive measures were taken to protect the bridge, including the demolition of several arches, the replacement with a drawbridge of three spans, and the construction of parapets for the garrison's defense.

Soon after, the Pardaleras Fort was constructed at the southern end of the city. Additional defensive elements, such as moats and walls, were added in a somewhat haphazard manner, which reduced their effectiveness. Inadequate materials and the lack of order in these constructions led to significant losses of land and buildings. At the end of the 17th century, between 1690 and 1700, work began on a bastioned fortification. This new defensive wall extended from the medieval wall along the left bank of the Guadiana River to the bastions of San Vicente and Palmas Gate. It then turned west and south, passing through the bastions of San José, Santiago, Santa María, and Trinidad Gate, before reconnecting with the defensive wall protecting the Alcazaba. According to existing military cartography, the watchtowers from the Islamic period remained in use until the Peninsular War. Of the numerous watchtowers Badajoz once had, primarily from the 12th century, only remnants of five are preserved, including the Espantaperros Tower and the Tower of Los Rostros.

History

Portugal and Castile engaged in a series of confrontations during the 14th century. In 1580, Philip II relocated the Court and the majority of his army to Badajoz, where he resided for eleven months, effectively annexing Portugal into the Hispanic Monarchy. Tensions concerning Badajoz resurfaced in 1640 due to its proximity to the border, as a result of the Portuguese uprising against the Crown of Castile.

Construction of the bastioned enclosure began in the 17th century, replacing a previous defensive system. This development was necessitated by the need to defend the city, seat of the General Captaincy of the Royal Army of Extremadura, amidst the hostilities that led to the Portuguese Restoration War, a conflict which aimed to secure Portugal's independence from Spain. Consequently, Badajoz solidified its role as the capital of the Province of Extremadura and became a significant strategic location for both Spanish and Portuguese interests. The war persisted from 1640 to 1668 when the Treaty of Lisbon recognized Portugal's full independence from Spain.

Due to its frontier location, the Badajoz Cathedral—constructed between the 13th and 18th centuries—resembles a fortress, featuring strong walls, battlements, and a prominent bell tower. Declared a Historic-Artistic Monument in 1931 and classified as an Asset of Cultural Interest, it stands out as a unique structure from its era. The Diocese and Bishopric of Badajoz date back to the 10th century, and the cathedral currently holds the rank of Metropolitan Cathedral. It houses Islamic pottery from the 10th century and the Metropolitan Museum of the Cathedral. Nearby is the historical archive.

The geographical features of Badajoz's terrain have historically marked it as a site of military and strategic importance. This significance made it a key point in the Spanish defensive system, especially given Portugal's strong defensive system of Elvas. Badajoz thus became a major stronghold on the border with Portugal. Its location, nearly at the same latitude as Lisbon and approximately equidistant from Madrid and Lisbon, though somewhat farther from Madrid, further accentuated its strategic value.

Defenses The bastioned enclosure was constructed on the foundations of the old medieval walled enclosure, which dated from the 9th to the 15th centuries and remained in existence until the 17th century. Some sections of the medieval wall were preserved, such as those near the bastion of La Trinidad and the bastion of Santiago. After nearly two and a half centuries of neglect, the old medieval wall, which extended from the current citadel, had deteriorated and become outdated due to the advancements in artillery technology used by the Portuguese army. In 1643, the Count of Santiesteban wrote to Secretary Pedro Coloma regarding the defensive structures at Badajoz, pointing out that, at that time, Extremadura lacked secure defenses, provisions, artillery, and other weapons. Badajoz appeared to have the minimum defensive conditions necessary, but the existing walled enclosure was deemed ineffective. The only part of the fortifications that might have had adequate defensive capabilities was the upper section occupied by the Alcazaba. Consequently, it was recommended that new defensive works be initiated in that area.

On the other hand, the Marquis of Torralbo wrote to the king in the following terms:

He concluded by saying that it was within the reach of artillery, for which the rammed earth walls were ineffective:

Gradually, the old defensive wall was replaced by a new fortification that began at the Muslim citadel, followed the left bank of the Guadiana River, and then turned west and south, where the bastions of San Vicente and Palma Gate were constructed. The construction continued westward, southward, and eastward, with the bastions of San José, Santiago, San Roque, Santa María, and Trinidad being added in succession. This new defensive system eventually connected to the old Alcazaba in the northeast via the bastion of San Pedro.

The newly built defensive elements were adapted to contemporary military engineering trends. The walls were made lower and wider to withstand cannon fire, and large bastions were introduced. The curtain walls were buttressed rather than vertical to deflect cannonballs upward. Additionally, half bastions were placed to guard the access gates, bartizans were added at the vertices where two curtain walls met, and features such as moats, lunettes, and ravelins were included to hinder enemy actions. Despite the robust nature of these defenses, the walls were also adorned with a semicircular stone facade, with its curved part facing outward.

The defensive system followed the design principles established by the French military engineer, the Marquis de Vauban.

Elements

The bastioned enclosure is composed of several defensive buildings such as the curtain wall of the defensive walls, the gates, designed to allow and control the entry and exit of the inhabitants, the bastions consisting of pentagonal constructions, which join two consecutive lines of defensive wall on the inner side of the pentagon, the forts located on the outside of the defensive walls and that were the first line of defense of the population and the ravelins that are triangular fortifications located in front of the body of the main fortification –generally on the other side of a moat– whose objective is to divide an attacking force and to protect the curtain wall of the defensive walls using crossfire. There are also other defensive elements such as moats, foothills, drawbridges, escarpments, and various smaller buildings either attached to or independent from the main enclosure.

Bastions