Investigation of the parameters of the city walls and their construction

The turbulent history of the city of Chania from 1252, when it became a Venetian colony, to 1645, when it fell to the Turks, influenced and determined the development of each phase of its fortifications.
For the first two centuries of this period (13th – 14th), the main opposing factor an urban centre with a pronounced Venetian element was “the enemy within”, that is, the continual insurrections of the Cretan population. By the 15th century, with the gradual rapprochement of the Venetian and Cretan populations and the establishment of peace, another problem had appeared as the prime cause of warfare: the intensification of the pirate raids that were to determine the fate of all the islands in the Eastern Mediterranean until well into modern times. Finally, since the earliest decades of the 16th century, and after four Veneto-Turkish wars, the number one enemy for any Venetian territory in the East was the Turks.
The second parameter that, in conjunction with the historical, shaped the evolution of the fortifications of Chania, was technology: that is, the development of military architecture and the achievements of defensive technology, together with the extremely rapid evolution of the art of war that marked the 15th century as a consequence of the supremacy of artillery.
In the first phase, the Venetians of Chania raised against the domestic enemy the repaired early Byzantine castle (Castelli), a classic medieval fort consisting of a crenulated wall flanked with towers. Later, the need to protect the city against pirates forced the authorities to add an outer defensive ring that would embrace the borghi, the poor quarters that had gradually grown up outside the walls. Finally, defence against a powerful enemy like the Turks required the construction of the strong modern fortified wall laid out by Michele Sanmicheli in 1538, on the defensive principles of bastioned fortification.
Within the fortified core, sections of whose walls still stand on Castelli Hill, the defences were based on factors that had been familiar since antiquity: the naturally strong and elevated position of the castle, the height of its walls and, principally, the alternation of wall and tower that assured defence with the conventional weapons of the age (longbows, cross-bows). Towers, also, guarded the gates, and the harbour entrance was protected by a single massive round tower (torrione), which is partially preserved and which, despite bearing the date 1477, was probably built in the second half of the 13th century.
With regard to the second phase fortifications built to enclose the borghi, the existing data is insufficient, since they were probably incorporated into the later enclosure wall designed by Sanmicheli.
The enclosure wall of the final phase (after 1538) presents all the characteristics of a typical bastioned fortress. Rectangular in shape, it lies along the coast, with its longer sides on the north and south and the shorter on the east and west. Its landward sides, which face onto flat and regular ground, are surrounded by a broad protective dry ditch and display the symmetry that was sought in fortifications of this type for the assurance of equal qualities of defence. All curtain walls are reinforced by a terreplein.
At the southern corners of the enclosure wall, two strong orillion bastions (bastioni a orecchioni) enfilade their fire with the fire from the flanks of a platform bastion (piattaforma) placed in the centre of the long southern wall and defending the intervening curtain walls (cortine). The insertion of a piattaforma on this side was essential on account of its length, since it was only by dividing it into two sections that the basic operational principle of the so-called “fronte bastionato” could be preserved: in order for there to be an effective defence of the bastions and full control of the curtain walls and the ditch, the distance from the flanks of the bastions to the salient points of their adjacent ones had to be less than the maximum range of the principal firearm of the period, the musket (about 260 m), just as the distance between the towers on ancient and medieval forts was determined by the range of the bow.
Above and behind the two southern bastions (baluardi) stood two cavalier towers (cavalieri), round embanked towers for artillery, which could train their powerful fire on distant targets, including the enemy trenches in case of siege.
At the northern corners of the rectangular enclosure wall stood two demi-bastions (mezzi baluardi), that is, bastions with a single flank, which assured the enfilade fire necessary to defend the eastern and western curtain walls; the walls facing the sea are straight, since the danger of assault from this side was considered minor.
The main gates into the city, one near the northeast demi-bastion and one near the Piatta Forma, were positioned so that they were defended by the nearest flank, and of course their positions greatly affected the structure of the urban fabric within the walls.
The form and function of maritime fortifications are quite different from those of land defences, and this is as true of the port city of Chania as of anywhere else. The fortification of the harbour entrance was assured by a polygonal ravelin (rivellino), today called Firka fortress, with a series of low vaulted embrasures to allow the artillery to rake the surface of the sea, which is the best way to defend against naval attack. This ravelin incorporated the old round tower that once defended the harbour. In addition, a chain extending from the round tower to the base of the lighthouse could close off the narrow passage when required. A corresponding but less strong ravelin (in reality simply a broken wall) was built in front of the northern face of the northeast demi-bastion. Finally, a small gunplace reinforced the wall of the breakwater, about midway along its length.
Sanmicheli’s fortifications remained virtually unchanged in form and function throughout the period of Turkish rule and right up to the dawn of the 20th century.