Perhaps no defensive structure summarizes the truth of siege warfare in the ancient and medieval world as clearly as the walls of Constantinople. The city lived under siege for almost all its life; its defences reflected the deepest character and history of the place, its mixture of confidence and fatalism, divine inspiration and practical skill, longevity and conservatism. Like the city itself, the walls were always there, and for anyone in the eastern Mediterranean, it was assumed they always would be. The structure of the defences was mature in the fifth century and changed little thereafter; the building techniques were conservative, harking back to practices of the Greeks and Romans. They had no particular reason to evolve because siege warfare itself remained static. The basic techniques and equipment – blockade, mining and escalade, the use of battering rams, catapults, towers, tunnels and ladders – these were largely unchanging for longer than anyone could recall. The advantage always lay with the defender; in the case of Constantinople its coastal position increased that weighting. None of the armies camped before the land walls had ever succeeded in effecting an entry through the multiple defensive layers, while the city always took prudent measures as a matter of state policy to keep its cisterns brimming and its granaries full. The Avars came with an impressive array of stone-throwing machinery but their looping trajectory made them far too puny to breach the walls. The Arabs froze to death in the cold. The Bulgar Khan Krum tried magic – he performed human sacrifices and sprinkled his troops with seawater. Even its enemies came to believe that Constantinople was under divine protection. Only the Byzantines themselves were ever successful in taking their own city from the land, and always by treachery: the messy final centuries of civil war produced a handful of instances where gates were flung open at night, usually with inside help.
There were just two places where the land wall could be considered potentially weak. In the central section the ground sloped down a long valley to the Lycus River and then up the other side. As the wall followed the downward slope, its towers no longer commanded the high ground and were effectively below the level occupied by a besieging army on the hill beyond. Furthermore the river itself, which was ducted into the city through a culvert, made it impossible to dig a deep moat at this point. Nearly all besieging armies had identified this area as vulnerable, and though none had succeeded, it provided attackers with a vestige of hope. A second anomaly in the defences existed at the northern end. The regular procession of the triple wall was suddenly interrupted as it approached the Golden Horn. The line took an abrupt right-angle turn outwards to include an extra bulge of land; for 400 yards, until it reached the water, the wall became a patchwork structure of different-shaped bastions and sectors, which, though stoutly built on a rocky outcrop, was largely only one line deep and for much of its length unmoated. This was a later addition undertaken to include the sacred shrine of the Virgin at Blachernae. Originally the church had been outside the walls. With a typical Byzantine logic it had been held initially that the protection of the Virgin was sufficient to safeguard the church. After the Avars nearly burned it in 626 – the shrine was saved by the Virgin herself – the line of the wall was altered to include the church, and the palace of Blachernae was also built in this small bight of land. Both these perceived weak spots had been keenly appraised by Mehmet when he reconnoitred in the summer of 1452. The right-angle turn where the two walls joined was to receive particular attention.
As they patched up their walls under Giustiniani’s direction and paraded the sacred icons on the ramparts, the people of the city could be pardoned for expressing confidence in their protective powers. Immutable, forbidding and indestructible, they had proved time and again that a small force could keep a huge army at bay until its willpower collapsed under the logistical burden of siege, or dysentery or the disaffection of the men. If the walls were decayed in places, they were still basically sound. Brocquière found even the vulnerable right angle to be protected by ‘a good and high wall’ when he came in the 1430s. The defenders however were unaware that they were preparing for conflict on the cusp of a technological revolution that would profoundly change the rules of siege warfare.
‘Navigantium fortitudo mihi soli inest’, is a remark made by Nicephorus II (as reported by Liutprand). Nicephorus could make this boast in truth, since the emperors of High Byzantium succeeded gradually in building up a fleet of such power as to check the depredations of Arab pirates almost completely in the eastern Mediterranean. During the latter part of the eleventh century, however, the Venetians and the Genoans gradually caught up with the Byzantine marine power and, despite the strenuous efforts of the Comnenian emperors to increase their naval forces, these represented the stronger force by the death of Manuel I, while the Byzantine naval presence after the death of Michael VIII was derisory and in time it vanished altogether, so that John VIII had to make his way to the Council of Ferrara-Florence by hired craft. The fleet of the naval era was divided into two main sections: the Imperial fleet and the fleet of the themes. The former was organized into two divisions, one for the personal use of the Emperor and Empress, and for the defence of the capital, the other for use on regular military expeditions and for policing the seas against pirates.
The fleet of the themes was kept up at the charge of various maritime themes, particularly those of the Greek islands (Aegea, Samos, Cephalonia), Greece and the Cibirriote theme in Asia Minor. The regular servicemen from these themes were paid in feudal land, as were the land forces in the army of the themes. An alteration was however made in the reign of Manuel I, whereby the monies expended by the themes on the upkeep of the fleet were diverted straight into the Imperial treasury, and the Emperor assumed the direct responsibility for the maintenance of the whole naval service. This was probably intended as an assurance for the better order of the ships, but, as might have been foreseen, it proved a disaster, as the money was repeatedly spent on wasteful civil-service projects, while the navy was starved of even necessary funds.
The fleet often employed foreign mercenaries, and Russian or Varangians who entered the Imperial service often began their time in the navy, this being a form of service which would have suited the temper of the Norse seamen. From what is recorded of Haraldr Siguroarson we may deduce that his first period of Varangian service will have been spent thus. The strategos of each maritime theme commanded his section of the thematic fleet, while the supreme commander was the commander of the Imperial fleet, who was titled in the High Byzantine era the Droungarios, and was of the rank of patrician. This official appears to have been known in the reign of Alexius I as the Grand Duke (Megas Doux), and his deputy as the Thalassokrator, while later still Pseudo-Codinus refers to an Admiral of the (by then insignificant) Fleet. These supreme commanders had other officers under them, and officers of the Hetairia were set to command the foreign naval mercenaries. In the tenth century 77 ships constituted the thematic fleet against 100 in the Imperial fleet, while the force manning the latter was 23,000-24,000 strong, against 17,500 in the former.
The capital ships of the Byzantine fleet were the dromoi, which differed considerably in size, but were built on the same pattern, with a wooden castle (xylokastron) on the deck, and carrying various military engines. In the bows was a figurehead of gilt bronze, usually the shape of the head of a wild beast, the lion being a popular motif, in which were housed the siphon and pumping mechanism to spray out the Greek Fire, the terrible Byzantine secret weapon which burned alike on land and water. This substance was also carried in fragile bowls or spheres of glass, which could be hurled on to the enemy ships and which then set everything that the stuff touched ablaze. The rowers were arranged in two banks, with a normal complement of 25 to each row; there were also on average some 50 soldiers on each dromos. It is calculated that there will have been around 220 persons to the full complement on a capital ship, or even more, since the account of the Cretan expedition of 902 refers to 230 oarsmen and 70 others, or in all a crew of 300 on each dromos. The Chelandia were smaller vessels, one class of which were named Pamphyloi’, they were often manned by foreign mercenaries, and their complement would be 130-160 men. Finally there were the light supporting vessels, the so-called ousiai, on which Varangians were frequently employed; these were swift and easily manoeuvred ships, which were especially useful for coastguard duty or for chasing and overtaking pirate vessels. The Taktnkca speaks of 50-60 soldiers forming the complement of each of these ships, and their total crew will there- fore have been c. 110 strong. On formal expeditions two ousiai generally accompanied each major vessel.
The commander of each dromos bore the title of Kentarchos, while over each division of 3-5 capital ships there was placed a homes? though the titles komes and droungarios are later used without discrimination of the captains of single ships. The fleet had its banner, the sign being a cross surrounded by four fire-siphons.
It appears that admission to the Imperial fleet, and especially appointment to one of the ships based on the capital, or in the personal service of the Emperor and his court, was very much sought after by personnel in the other divisions of the Byzantine navy. As the pay was higher, and the serving personnel could more easily obtain high court distinctions in these ships, this is understandable, and it is very likely that it was necessary to purchase such appointments in the same way as ones in the land Hetairia. It is, however, even more difficult to calculate the naval rates of pay than those of the land forces, though some inkling may be derived from the above mentioned narratives of the two naval expeditions to Crete. The pay of the Russians and Varangians in the sea-forces will certainly have been far smaller than that of those in the Hetairia. If it is true, however, that the commanders of the coastal protection vessels were entitled to keep a considerable proportion of the goods confiscated from pirate vessels, then this could obviously make a very sizeable difference to their emoluments. It is noted in Haraldar saga Siguroarsonar that he was to pay the Emperor 100 marks for every pirate vessel that he was able to capture, but could keep the rest for himself and his men. This could obviously be a very valuable source of income.