The Sagres Promontory is in a great strategic position since it has two coves that constitute excellent anchorages and landing points, also being an excellent point of observation and control of the coastal navigation between the Mediterranean and the Atlantic.
On the other hand, the piece of land that extends on sea constitutes itself a position of natural defense due to the high cliffs that surrounds it, being sufficient for that a small fortification by the side of earth to make the place virtually impregnable.
Returning to the year 1443, on October 27, prince Henry receives from his brother, the regent D. Pedro, a letter of donation from the Trasfalmenar cape and a legua of term (Sagres and its surrounding region). Indeed, the Infante, having been aware, probably since 1415, of the contingencies to navigation provoked by the strong prevailing winds in the region of Sagres, soon realized the necessity that the boats that folded the corporal felt in staying sheltered in the bays of cape of Sagres
This stay could drag on for long periods, while waiting for see and winds favorable to navigation. In this way, the Infant defended the need to provide some support to these navigators who, during their wait, were deprived of food and religious assistance.
On the other hand, he considered the strategic importance of this region, since it was a practically obligatory point of reference for commercial vessels, connecting the Mediterranean and the North Atlantic, beyond its proximity to North Africa and the advantages that could result therefrom for the Portuguese expansionist project in that region which had begun with the conquest of Ceuta.
This explains the interest of the Infante in the region of Sagres, as well as his initiative to establish there a fortified village to support and defend navigation, which he named “Vila do Infante”.
This Henrique's fortification is most likely to be found in the drawing dated 1587, the author of which was an expedition accompanying of English corsair, Sir Francis Drake, during his devastating incursion into the region of Sagres and St. Vincent.
Although more than a century after the death of the Infante, it is very probable that the fortress represented here is of Henrique foundation, because, from the available documentation, no changes were made to the original fortification during this period, with except for two bastions that were attached to the wall in 1573 by order of D. Sebastião. It was then a wall with medieval characteristics but already with some innovations destined to the combat with firearms, what is characterized like a fortification of transition between the medieval military architecture and the modern military architecture.
Indeed, the development of artillery and the full use of firearms in war scenarios marks the beginning of a new era in military strategy and architecture. The introduction of the bulwark as an essential element of any fortification is the response, in the defensive field, to the developments of the offensive techniques, reason why the military architecture enters definitively in the Modern period, appearing the first fortresses and batteries "abaluartadas". The bastions were then structures, initially of circular form and, later of angular forms, that stood out in the walls. Designed to use modern artillery, they were strategically placed to allow cross-firing of their artillery, increasing their effectiveness and allowing considerable firepower.
In 1573, by order of D. Sebastião, the first bastions appeared in the Fortress of Sagres. Arranged at the ends of Henry's wall, they shielded the front door through the crossfire between them. Later, during the reign of Philip I of Portugal (1581-1598), the monarch built a tower over the barbican of Henanque, under which the entrance of the fortress was processed by a tunnel that connected the entrance door to the interior of the fortress casing. . At the top of this tower, or Central Tower, was a platform properly prepared for the placement of fireworks, increasing the defensive power of the Sagres's Fortress.
However, the wall layout remained unchanged and, despite these changes, still remained a fortification of transition. In 1621, the Neapolitan engineer, Alexandre Massai, proposes the construction of new bastions for the Sagres's Fortress, presenting two possible moths. These were two larger and wider bastions and could house a greater number of hydrants. But it was only after the restoration (1640), in the reign of king João IV, that work began on the construction of a new road to the wall and walls of the Sagres's Fortress . Although it coexists with the wall of Henry, the new fortification already presents/displays the characteristics and the configuration of a modern fortress “abaluartada”. Its construction remains incomplete for a long period of time, in addition to having suffered serious damages with the great earthquake of 1755. Thus, only in the end of century XVIII, in 1793/94, the Sagres's Fortress was completed with a new layout and configuration. The primitive wall of Henry was finally demolished, giving place to a modern maritime fortress designed and constructed for firearms.
As the previous fortification, in addition to incomplete, was in an advanced state of ruin, it was necessary to build a new defensive system, whose design was based on the method of fortification of marshal Vauban. As we shall see later, this consisted of the perfect application of a complex system of angles and measurements in the bastions, so that its position in the curtain or wall allowed the crossfire of its batteries to obtain the greatest effectiveness, canceling the blind angles in the sectors of footage. On the other hand, the implementation of a defensive system must obey the characteristics of the terrain that surrounds it. Thus, in 1794, the Sagres's Fortress was finally completed, presenting all the characteristics of the modern system “abaluartado”, totally thought for the use and combat with firearms. In fact, the tall towers and the medieval walls, built of massive blocks of carved stone, gave way to smaller, thicker defensive structures made of mortar and plaster, designed and built to better absorb the impact of enemy projectiles, while their artillery, just above the level of the terrain, presented an impressive fire power, crossed and grazing, on the enemy.
But the differences of the medieval period are not limited to military architecture. The development and current use of firearms on the battlefield has forced a reorganization of military strategy, particularly in the defensive field. While in the Medieval Period the fortifications - castles - were intended mainly for the defense of the populations that inhabited its interior or nearby, in the modern period, the strong fortifications - had as main objective to guarantee the defense of a more comprehensive area and not only of a particular place , or locality, in a narrow sense. In this way, the implantation of a fortress followed a complex defense plan, in which, through the communication and interaction of several fortifications, the so-called "defensive line" resulted. And the Fortress of Sagres is precisely the coordinating center of a defensive line, which extends to the western end of the Algarve coast. In this sense, more than a Fortress, we are facing a War Plaza, on which the forts of Baleeira, Beliche, São Vicente, Carrapateira and Arrifana depend directly.
On the other hand, the Fortress of Sagres is included in the category of maritime fortress. But it location is not near the coastline that gives it the character of Maritime Fortification, but its purpose, that is, a whole strategy focused on the defense of the coastline and navigation control. Due to an essentially strategic ground deployment, it has smaller dimensions compared to land fortifications, since its function consisted in defending specific firing ranges, in this case, Sagres coves (Mareta, Tonel and Beliche) in isolation or in conjunction of fires with other dependent fortifications. In short, and despite the objectives of this fortification have been maintained over time, Fortaleza and Praça de Sagres has seen quite significant changes in its defensive structure, trying to keep up with technical developments in the field of military strategy.
Sagres Fortress "Sagres Promontory" belongs to the Sagres War Memorial of the Kingdom of the Algarve
Nowadays the promontory of Sagres presents itself as a historical symbol of national expansionist policy, of discoveries and a legacy of portuguese maritime navigation study.
It is open to the public for visits and sharing a legacy of a historical era of the Portuguese nautical discoveries.