The Castle’s Architecture

Castles and medieval world


Imagine what life must be like for the houses where that life is housed to have walls three metres thick, bars on all sides, hardly any windows, and the few that do exist are very narrow and several metres above the ground. The castle, which is essentially a fortified house, has its origins in a violent world, and in the conjunction of a necessity and a possibility. The need that arose, around the 9th century, to provide a solution to a situation of disorderly and generalised violence, at a time of transition between the society resulting from the end of the Roman and Carolingian empires and the formation of medieval civilisation. And on the other hand, the possibility, due to the disintegration of the public powers, of dealing with this violence in a private way and without any legal or moral restrictions.

Although there are authors in favour of calling any fortified building from any period a castle, here we are going to consider it as a phenomenon almost exclusive to Western feudal society, for one main reason. What makes the castle different from any other type of fortification is its dual nature. The castle is, in general, a highly fortified residence, or a highly habitable fortress, and, above all, it is of a private nature. Well, “it is this essential duality of being a residence and a fortress which is intrinsically unique to the castle, and it is the private and stately function which is proper to it, as opposed to the communal function, which distinguishes the castle in the history of fortification” (Reginald-A. BROWN, Castles, ob.cit., p.5). This duality will require the castle builders to make a compensatory effort which will quickly be understood: a house with an access several metres high, with the smallest number of openings in thick walls, is extremely defensible, but very difficult to live in. And, on the other hand, comfort is obtained by lowering the demands on defensive qualities. Since castles needed both, the architecture of castles tried to strike a balance. Depending on the period, the time, the type of castle, and the historical circumstances, the balance will tend to tip one way or the other. While in France and England, for example, the tendency over time was to make castles intensely fortified residences, with ever greater concessions to habitability, in Spain castles were more like slightly habitable fortifications, with very few and very late concessions to comfort.

From a purely warlike point of view, the castle was the most complex and refined military machine of the Middle Ages, and constant innovations were applied to it in this respect. All of them were conditioned by what is known as the struggle of the projectile and the armour, a principle according to which every advance in attack techniques is answered, like a reflection in a crystal, by an equipotent response in defence techniques. For much of the Middle Ages there was a clear predominance of armour: surrendering a castle by force was tremendously difficult with the war machines that existed. But around 1300 cannon were invented, a type of artillery that used gunpowder as a propellant. For more than a hundred years these first cannons were of little effectiveness, but by 1450 fire artillery had become a weapon to be reckoned with from a military point of view, and castles had to adapt to this new reality. From 1500 a new type of fortress specifically designed to repel gunpowder artillery took shape. We call the castles that represent an intermediate step between the new specifically artillery fortresses and the medieval castles prior to the triumph of gunpowder, without being either of them but both at the same time, transitional castles. The Santiago castle belongs to this type.


Castillo de Santiago

Strength area analysis

It is safe to say that the Castillo de Santiago de Sanlúcar is one of the most interesting of its kind in Castile, and the one with the largest built area in the province of Cádiz. It is a castle that denotes the tremendous personality of its builder, and which is replete with interesting and advanced, for the time, defensive systems. It was the main fortress built, along with that of Niebla – a castle that is in many ways a twin, which defies the maxim that no two castles are alike – by the 2nd Duke. These elements of interest include the following:

La Torre del Homenaje
We call Torre del Homenaje to the main and strongest tower of a castle, which is why it is usually the largest tower in the castle. The lord or his warden would reside in this tower in his absence – in the case of Santiago, in the great hall on the third floor. These towers usually function, in most cases, and from a tactical point of view, as the last refuge within a fortification, which means that it must be the most defensible, and that it must also enjoy a certain degree of autonomy with respect to the rest of the fortress.

The Torre del Homenaje, on the other hand, tend to concentrate the few elements intended for domestic comfort that appear in Spanish castles; the tower of Santiago is especially austere in this sense, and is very much in line with what Professor Mora-Figueroa said: “it seems evident that the [Castilian] towers of homage are in their interior design an uncomfortable shelter from the bad days, with hope in the brevity of the trance, conceived for a bad night in a bad inn”. But it has something: the tower has a supply shaft, that vertical hole originally intended to facilitate the transfer of water, ammunition and other useful things. And with tabucos ventaneros, which are those benches on either side of the windows, very typical in 15th century castles, and which have no mystery, they are exactly what they seem: they are used to sit and look out of the window, while weaving, chatting with the neighbour on the bench, reading a book, or simply watching the people passing by. According to a plausible tradition, Isabella the Catholic saw the sea for the first time from the keep of this castle.

Pyroballistic adaptations
The castle of Santiago has a formidable collection of pyroballistic adaptations, which makes this fortress one of the most interesting of its kind in Andalusia. This term encompasses all the architectural arrangements designed to withstand the artillery punishment to which the castle may be subjected, as well as all those designed to optimise the use of the castle’s own artillery. The artillery barrier or falsabraga, the lower wall that surrounds the entire castle, stands out in this respect, in which there are fifty or so firing chambers with arrow slits, openings in the walls through which the mouths of the cannons protrude for firing. In addition, the castle is designed to deflect enemy fire – by means of sloping surfaces known as alambor – and to evade it – for this purpose the castle was originally crouched at the bottom of a deep moat – as well as to minimise the dead angles around it – for this purpose the geometry of the wall is carefully designed to favour flanking fire.

Transit areas, subtle entrances and dungeons

The eventful life of a fortress could require entering and leaving the castle discreetly. In Santiago there are two subtle entrances and exits. The first of these is the poterna in the wall surrounding the keep. A poterna is an inconspicuous gateway from which to enter and leave the fortress in exceptional situations. The second is the underground passageway that links the ducal palace with the castle. This gallery was built in the mid-17th century, when Sanlúcar was under threat of confiscation by the Crown – which would come to pass – and the IX Duke felt the need to have a quick and direct access to the castle at hand, in case the situation became complicated.

The castle’s daily life would revolve around the parade ground. Unfortunately, the medieval castle itself was lost centuries ago. However, the splendid naves built by the Duke of Montpensier around 1853 have been preserved.
We have preserved some of the original dungeons of the castle, narrow bell-shaped rooms with a single narrow access hole in the ceiling. We know of the existence of a larger one, where, according to documentation, slaves were locked up during raids by Barbary pirates – to prevent them from joining them – but these have not yet been found.

In the 17th century, when the IX Duke saw the conflict with the Crown coming, he had an escape passage built to link the castle and the Ducal Palace, located a few hundred metres away. Unfortunately, only the first section has survived, as it was condemned by the foundations of the modern houses. A branch, also cut off, went out towards the beach.

The Aula Maior
We call the great hall that precedes the tower of homage, the Aula Maior. This construction is very special for two main reasons. The first is that this type of tower is very rare in Spanish castles, there being less than a dozen in the whole of Spain. Secondly, it has partially preserved original 15th-century mural paintings in its vault, which depict the personal emblem of the 2nd Duke, the segur, a kind of hatchet that is also represented in the Mermaid’s Gate. The dimensions and height of this room (22 metres) make it an architectural feat, and its function was to impress visitors, as well as probably to house the ceremony of the homage lawsuit, the oath of allegiance of the governor of the fortress to his lord.

Castle attack and defence systems
To prevent outsiders from entering, or at least to make it as difficult as possible for them to do so, various devices were devised and tactical approaches were developed. Among the latter, the principle of defence compartmentalisation stands out. According to this principle, the fortress must be designed in such a way that the attacker encounters successive obstacles in a staggered manner, and so that the defenders can successively withdraw by sacrificing sectors of the fortification. For this reason, each sector must dominate the previous one, in such a way that the situation of superiority of the defenders is not lost at any time. In Santiago, the compartmentalisation of the defence was originally achieved by means of a configuration of the building that made it necessary to take a number of turns before penetrating the core of the fortress. The last redoubt was the keep, which could be segregated and defended from the rest of the castle by means of a system of armoured doors, drawbridges, ramps that cut off the passage, and loopholes that defended the accesses. On the other hand, the general defence of the castle was actively exercised by means of some architectural devices, such as the burglars – in the corners of the flanking towers – and machicolations – in the Aula Maior -, which made it possible to vertically harass the foot of the walls. The arrow slits, on the other hand, allowed horizontal harassment (see table “pyroballistic adaptations”).

Stone Labyrinth and Symbology
There are a rare number of graffiti on the mortar in Santiago, original from the time of the castle’s construction. These graffiti are very diverse, ranging from drawings of ships to construction instructions; one of them is particularly striking, as it is written “biua el duq”, which means “Long live the Duke!

Two elements have a special symbolic relevance: on the one hand, we know that the Aula Maior was crowned with fleurs-de-lis in stone, one of which was recovered some time ago during archaeological excavations. With this decoration the dukes intended to claim a link between their lineage and the dukes of Brittany. The Mermaid’s Gate is also particularly symbolic. For the design of this doorway, one of the most meticulous in Andalusian military architecture, the dukes, moved by artistic concerns, brought in an Italian artist, a certain Marinu from Naples. The cover also depicts the personal symbol of the 2nd Duke, the segures, which are said to have been accompanied by the motto “the most dangerous things with me ensure their danger”. But perhaps the most striking feature of this cover is the nereid bearing the arms of the 2nd Duke and his wife, Leonor de Mendoza. The use of a mermaid as a heraldic bearer is very rare in Spain. It refers to a symbolic significance that is difficult to demonstrate, although one accepted version suggests that it embodies the personification of desire that cannot be achieved and also, in a general way, the concept of duality.

Photo Gallery


Atardecer sanlucar
Castillo Santiago
Muros castillo santiago
Puertas castillo
Muros castillo de Santiago
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Muros castillo santiago


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Armadura castillo santiago
Biblioteca Castillo Santiago
Comerdor castillo
Sala de reuniones
Castillo medieval
castillo medieval sanlucar
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