Imperial bodyguard: Viking mercenaries in a 12th-century Skylitzes manuscript.
A map of western Asia Minor, showing the routes taken by Christian armies during the Crusade of 1101.
Another serious misunderstanding arose from the Byzantine policy of maintaining diplomatic relations with the Muslim caliphs, other Arab leaders and Turkish emirs. The western knights did not appreciate the long tradition of exchanging embassies with the enemies of the empire, which had established a web of diplomatic contacts and intelligence. On this basis, the Byzantines were often able to avoid war, to exchange prisoners and maintain peace. This was condemned in the West as treachery. The charge resurfaced in a more pointed fashion during the 1180s, when Andronikos I was reported as being in league with Saladin and the Turks. Magnus of Reichersberg, a German monk, simply denounced the Greeks as treacherous and hostile to western forces. The accusation contains a degree of propaganda and may be a forgery. But clearly the Latins were surprised that Byzantine emperors traditionally engaged in diplomatic contacts with Muslim leaders of the Near East and did not appreciate their behaviour.
These ambiguous feelings also generated suspicions and fears which accumulated as Byzantine requests for western military help against the Turks continued through the twelfth century. During the Second Crusade, in 1147, King Louis VII of France and the German Emperor Conrad came to the capital, where Emperor Manuel laid on extravagant entertainments and made sure the rulers visited the most important monuments and relics of Constantinople. Echoes of this royal visit appear in Icelandic sagas and the epic of Charlemagne’s pilgrimage to Jerusalem. Western knights were astonished at the wealth of the empire, particularly the churches and markets of the great metropolis of Constantinople, while the Byzantines feared that the crusaders might become covetous. In Frederick Barbarossa they recognized a brilliant and ambitious leader who might well turn his forces against the Queen City.
Meanwhile, the Turks consolidated their hold on the central plateau of Asia Minor. In 1176 Manuel confronted Sultan Kilij Arslan near Myriokephalon and was soundly defeated. This confirmed a permanent Turkish presence in the Sultanate of Rum, which forced bishops to flee and pressured Christians to convert to Islam.
In the last two decades of the twelfth century, both western and Byzantine forces had reason to be wary of each other. During the Third Crusade, Emperor Isaac II Angelos (1185–95) was fiercely criticized for negotiating a truce with the Mamluks of Egypt while the crusaders restored Christian control in Acre. It was in order to secure Jerusalem that Pope Innocent III preached the Fourth Crusade in 1198. One year later Alexios III Angelos (1195–1203), who replaced his brother Isaac II as emperor in Constantinople and blinded him, sent an embassy to Rome requesting support for an attack on the Turks. The pope responded that Alexios would have to contribute to the crusade and that the Eastern Church would have to return to the authority of Rome. This threat to the independence of the Church of Constantinople coloured all later negotiations between the crusaders and Byzantium.
Knights from northern Europe, led by Geoffrey Villehardouin, adopted a novel strategy for the Fourth Crusade: it would attack the Muslims from Egypt. So they requested the help of Venice in transporting their forces across the Mediterranean to Alexandria, and this was agreed at considerable expense. But too few crusaders arrived at Venice to pay for the transport in specially designed ships. The Venetians then proposed to make a slight detour from the planned route to attack Zara, a Christian city on the Dalmatian coast. In order to set sail, the crusaders had to agree, and with the plunder they accumulated at Zara they were able to finance the crusade. But at Zara they also learned about Prince Alexios, son of Isaac II, who had escaped from prison in Byzantium and came to meet the leaders of the crusade. The young pretender, plotting against his uncle Alexios III, offered 200,000 silver marks in support if they would restore him to the imperial throne. He also accepted that the Church of Constantinople should become subject to the pope. After much discussion, it was agreed that the fleet should make another detour, to Constantinople, to install Alexios as rightful emperor, collect the sums promised and then proceed to Alexandria. Many knights, however, left the expedition at this point, disillusioned by the delays in getting to the eastern Mediterranean.
In the spring of 1203, the fleet duly set sail from Zara, anchored outside the walls of Constantinople, and within a few weeks installed Alexios IV Angelos on the throne. But then he had to fulfil the terms agreed at Zara, which proved much harder. After nearly a year when Alexios failed to pay the crusaders, a delegation went to warn him:
Our lords have frequently called on you… to carry out the contract made between yourselves and them. If you do this, they will be extremely pleased; but if not, they will no longer regard you as their lord and their friend, but will use every means in their power to obtain their due.
Geoffrey Villehardouin continued: ‘The Greeks were much amazed and deeply shocked by this openly defiant message… The noise of angry voices filled the hall.’ In his history of the crusade, written later, he reported that he was extremely glad to get out of the Blachernai Palace alive. Once the challenge had been made, hostile action became more likely, and when no payment was forthcoming it became inevitable. In April 1204, the crusaders attacked Constantinople with their most sophisticated siege weapons, which had been destined for Muslim-held Jerusalem. After four days, they forced an entry over the sea walls and subjected the Byzantine capital to a five-day sack. They then elected Count Baldwin of Flanders as emperor and the Venetian, Thomas Morosini, as patriarch, setting up a Latin Empire. The Byzantines were forced into exile.
In this development, the Doge of Venice, Enrico Dandolo, played a decisive role. He had lived in Constantinople in the 1180s and lost an eye in an attack on Venetian property. Now he suggested that the besiegers agree a division of the estimated spoils of war, a Venetian technique which had also been used at Zara. The Partitio terrarum Imperii Romaniae was drawn up in 1204 to justify and consolidate anticipated gains, not only of the city’s wealth but also of the territory of Romania, a western name for the empire. When the city’s impressive fortifications looked secure, it was Dandalo’s expert knowledge of the Golden Horn that proved critical to the success of the final attack. Venice was also the power that gained most from it, in that the conquest of Constantinople gave it rights of occupation over all the trading ports it used. The Venetian commercial empire, established as a result of the Fourth Crusade, was far more successful and permanent than the Latin Empire of Constantinople, which lasted less than sixty years.
For Byzantium, however, the experience of the sack of April 1204 left indelible wounds. Both Greek and Latin authors preserve vivid eyewitness accounts: Geoffrey Villehardouin, Robert de Clari, Gunter of Pairis (a monastery in Germany) on the western side, and Niketas Choniates, the greatest Byzantine medieval historian, on the eastern. Both sides agree about the extensive looting and devastation, which was increased by fires. Gunter writes:
so great a wealth of gold and silver, so great a magnificence of gems and clothing, so great a profusion of valuable trade goods, so great a bounty of foodstuffs, homes so exceptional and so filled with commodities of every sort… suddenly transformed [the crusaders] from aliens and paupers into very rich citizens.
Constantine’s fine city, the common delight and boast of all nations, was laid waste by fire and blackened by soot, taken and emptied of all wealth, public and private, as well as that which was consecrated to God, by the scattered nations of the West… the dashing to earth of the venerable icons and the flinging of the relics of the saints… seizing as plunder the precious chalices and patens… the outcries of men, screams of women, the taking of captives… and raping of bodies.
After five days, Choniates and his family only escaped from the destruction thanks to a Venetian friend, a wine merchant, who pretended that these Greeks were his booty.
The Latin occupation of Constantinople had many long-lasting effects, not least the removal of many relics, antiquities and treasures to the West. In 1207, for example, Heinrich von Ülmen offered a magnificent gold and enamel reliquary of the True Cross, made in about 963, to his local bishop. Its presence today in the treasury of the cathedral of Limburg is a reminder of the looting of the greatest Christian city of the medieval world. Four ancient bronze horses that had guarded the Hippodrome and inspired competitors from the fifth century, were taken to Venice to adorn the façade of San Marco, where replicas are now visible. The crusaders removed sixth-century carvings from the church of St Polyeuktos, sculptures, icons, silks, manuscripts and precious liturgical objects – all part of the vast booty divided between the crusaders.
In this way the leaders of the Fourth Crusade subverted the ideals of the First. The spirit of Christian pilgrimage and adventure, inspired by Pope Urban II’s sermon at Clermont, was destroyed by the Latin occupation of Constantinople. Although this did not put an end to crusading, its dark shadow hung over all attempts to re-create Christian unity against Islam.