FORTIFICAtiONS BAstion on the border between Extremadura and Alentejo

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The defensive traditional constructions inherited from the medieval stage, were based on the traditional castle, normalemnte raised on rocky formations, and the citadels defended by curtains of high walls and towers that were protecting them, raising his height even over those, to prevent the scale of the enclosure for the forces assailants.

With the advances of the artillery, which in the decade of 1450 already was provided with a considerable destructive power, one saw that the high medieval walls, they were succumbing before the enemy fire.

It considered, in Italy, to reduce initially the height of the defenses, especially of his towers, in order that they were offering white minor to them new pieces of artillery. The dimensions of the pits were accentuated and the new towers and curtains were adapted, to be able to use as seat the defensive bateías.

The fortifications, sometimes confused with the constructions Vauban, were forming a complex plot of defensive constructions, planned by means of a perfect geometry, which basic aim was assailants allowed only the step of the forces, for a series of places that were perfectly beaten by the artillery of the square.

Basically they were formed by a system of trace in star, where a series of linens of muralllas (curtains), there were joining for some fortifications of polygonal form, so called bastions.

The tracing of the whole system, it was impeding the access to the squares asesiadas by means of pits and other obstacles, which were preventing to a great extent, the direct impact of the artillery of site and the incursion of the cavalry and infantry of assault.


Plane of the reforms of bastion fortification de Marvão (Potugal)


It is a question of an evident example, of the evolution of the medieval strengths to fortifications " to the modern one ". It can be observed since they have been added in the vertexes of the medieval fortification, bastions more or less big, with the aim to reinforce the set. At the same time, there are completed the defensive structures of the accesses to the different enclosures.

Pentagonal fortification Plant of Olivenza's fortification (Badajoz)
Fortification bastioned of the Badajoz (1812) Plane of Valencia de Alcantara
Plant and section of the pit placed between the bastions of San Jose and San Vicente (fortification bastion of Badajoz)
Detail of plant of the fortification bastioned of Badajoz


Fortification of polygonal form and pentagonal plant, placed in the intersection of two curtains. It consists of two flanks, two faces and a gullet (face where it joins the curtains)


Space or opening between two merlones, where a piece of artillery was nailed.


It is the part of the flank of the bastion that stands out between two gunboats.



Armoured construction, destined generally to the protection of pieces of artillery and of his servants. It can place on the own adarve, under this one and to different levels.


Police officer's body protected with bunker, from where it was possible to do fire safely, placed sometimes in the counter
scarp to protect the invasion of the pit or to use as gallery communication with another element of the fortification.


Obra defensiva situada no alto de um muro ou porta, que sobressai por sua vez exterior. Utilizava-se para arrojar projéteis, líquidos e outros materiais ardendo, sobre o inimigo.


Linen of rectilinear wall placed between two bastions.


High part of the curtain, bastion or revellín, after that the defenders were protected.

Faces of the bastion

Each of the walls that look at the exterior of the fortification. From his adarves one was controlling or preventing the approximation of the enemy, by means of the fusiliers and the pieces of artillery.

través caballero parapeto y banqueta


Exterior work placed generally on the counter scarp, which destination was to use as parapet to defend itself from the fires of lined up, from flank, from reverse or from rebound. Also it was one more obstacle to hinder the step, for the covered way remained very narrow.


Works interior defensive placed to a level higher than that of the principal líne of the fortification. This was allowing for his dominant situation, that his power of fire should cover the whole surrounding field. In the photography, illuminated in yellow color.

Parapet and Hassock

Wall or wall that was rising on the adarve, after that they were protecting and travelling the forces that were defending the fortification. On the same adarve and after the parapet, there was placing the Hassock, work of land or masonry that like continuous bank was allowing to shoot the suitably protected fusiliers.


Plane inclined from the cord up to the pit, in the interior margen of this one.


Projection, vertical or in sloping plane located in the exterior margen of the pit of a fortification.


I reinforce or added placed to I peeped of the scarp or principal wall, which in addition was serving to contain the fall of this one in case of persistent impacts of the artillery.


Deep excavation that circuvala a castle or strength placed between the walls or principal curtains and the exterior.


Between the top part of the wall or adarve and the sloping plane that was descending to the pit, was placing a molding of semicircular profile known as cord.


Area cleared in soft decline, which departs from the exterior elements of a strength. The glacises were preventing the approximation of the assailants and were concealing the fortification from the direct fire.

minascontraminas minascontraminas minascontraminas
Palisade. Fence realized with sharp logs, to block the rapid way of cavalry and infantry. First of the defenses conque was counting a strong square.
It mines. Tunnel escavado for the besiegers to place an explosive charge and to knock down a wall.
Counter mine. Tunnel that was dividing from the interior of the fortification to avoid the action of the enemy mines. Also "they" "were" "sowed" to make them to exploit under the attackers.

Half moon or lens

It was a question of constructions of triangular plant, that they were in the habit of having his flanks redressed in stone, and they could be provided with artillery. They were placing inside the pits, between two bastions.

Exterior or strong works

Constructions raised in geographical points that were rising on the principal fortification, being his principañes points of defense.


It is a construction similar to the lens, but destined generally to cover a bastion or a door.


Weak spot rounded of a bastion, destined to the protection of the exits of troop by a nearby postern.

Covered way

It is a question of a way of interior surrounding to the periphery of the fortification, for which the defenders can move workforce to cutlery of the fire besieger.


Platform where there was settling itself a set of mouths of fire, you destine to beat a certain aim. His location could coincide or not with the flanks of a bastion, or to place in a strategic place.


They were hollows excavated to the feet of the walls, in the pit. Covers of tables and undergrowths were concealing sharp stakes empozoñadas those that the attackers were falling irremediably.


Long and narrow loopholes opened in the walls and steps of the accesses to the different enclaves of a fortification. They were occupied by groups of fusiliers.

Guerite, Booth

Excellent structure a wall placed in a corner or near an entry. It was also an advanced position of vigilance on the pit ylos glacis.


Doors secondary, placed under the curtains to communicate the inetrior of the fortification with the pits, facilitating the sending of forces to different points, according to the needs of every moment.


I access to one of the doors of the square, which on having been raised by means of a wheel, was blocking the way to the interior of the same one.

Strengthened doors

To prevent the access to the city for the doors, these were forticadas, isolating them by means of a drawbridge or interposing a revellín with double door (sometimes in bend).

revesesplazadearmas revesesplazasdearmas
Square of weapons and slants from the pit of the bastion.
In red, on the plane, slants reverses and square of weapon.


oN the border of EXTREMAdura and ALENTEJo

The relations between the kingdoms of Portugal and Spain it has happened along the history for a prolix series of meetings and misunderstandings. Marriages between royal families originated on one hand alliances, and for other big successor disputes. All this gave place to big conflicitos penisulares encouraged by England and France that were afraid of an Iberian close peninsula and an empire that undoubtedly would dominate the world. These fights originated the fortification of the border, to bear in the times of crisis the advance of the invading armies. Between the XVIIth and XVIIIth century the new skills of artillery remained obsolete and the medieval fortificacione, they were turning out to be very vulnerable to this type of assaults.

The walls turned into curtains (mas low and sloping) and the towers into bastions, elements of pentagonal form that were tolerating better the impacts of the new missiles. This way the fortifications bastions that the kingdoms of Castile and Portugal arranged along the opposite stripe.


These big fortresses that normally were surrounding the cities, were composed by a geometric tracing, placing bastions in strategic points and joining these for curtains defendias for deep pits.

Sometimes, in front of every curtain, a lens was intervening or revellín, to protect her due.

The strengthened doors were placing in the sides of the bastions or in the middle of a curtain. In both cases, often a revellín was in front with door in bend and drawbridge.

The heights that were surrounding the fortification, were occupied by forts more or less big that were relalizados with the same defensive elements, protecting the city from the exterior and taking the enemy between two fires.

All these fortifications train a defensive set of the only characteristics in the world. His condition of conservation and importantancia strategic and military very different sound in every case. The unique city that preserves almost the totality of the military work, is Elvas. In the same locality they place the Fort of Nª Sª of Graça, known equally with the name of Fort of the Star. Constructed by Lippe in the 17th century it is possibly the impregnable foraleza mas of the whole Europe. Badajoz was the fortification abaluartada mas important for your size and military importance, but great part of your elements they were devastated in the first half of the 20th century.

Valencia de Alcantara, Olivenza on Spanish part is other important points, close to small works of reinforcement in other populations as The Codosera or Alburquerque.

In Portugal they stand out from north to south, Castelo de Vide, Marvao, Portalegre, Estremoz, Jorumenha or Monsaraz.


 Antonio García Candelas        Suggestions and impressions