Within months the expedition had sacked the Christian city of Zara on the Dalmatian coast, Venice’s political and economic rival. Innocent was dismayed when he heard about this affront and reacted by excommunicating the entire crusade. At first, this act of censure–the ultimate spiritual sanction at the pope’s disposal–seemed to stop the campaign in its tracks. But Innocent rather foolishly accepted the French crusaders’ pledges of contrition and later rescinded their punishment (although the Venetians, who made no move to seek forgiveness, remained excommunicate). By this time, dissenting voices within the crusader host had begun to question the direction taken by the expedition; some Franks even left for the Holy Land under their own steam. The majority, however, continued to follow the advice and leadership offered by the likes of Boniface of Montferrat and Doge Dandalo.

When the plunder gathered from Zara’s conquest proved insufficient, the crusade turned towards Constantinople and the Byzantine Empire. The ‘just cause’ cited for this extraordinary decision was that the crusaders planned to reinstate the ‘legitimate’ heir to Byzantium, Prince Alexius Angelus (son of the deposed Emperor Isaac II Angelus), who would then pay off the debt to Venice and finance an assault on the Muslim Near East. But there was a darker subtext at work. The Greeks had stifled Venetian ambitions to dominate Mediterranean commerce for decades. At the very least, Dandalo was hoping to install a ‘tame’ emperor on the throne, but perhaps he already had a more direct conquest in mind–certainly the doge was only too happy to usher the crusade towards Constantinople.

Once there, the expedition rapidly lost sight of its ‘sacred’ goal to recapture Jerusalem. After a short-lived military offensive, the existing imperial regime was toppled in July 1203–at only limited cost in Greek blood–and Alexius was proclaimed emperor. But when he proved unable to redeem his lavish promises of financial reward to the Latins, relations soured. In January 1204 Alexius’ grip on power faltered and he was overthrown (and then strangled) by a member of the rival Doukas family, nicknamed Murtzurphlus (or ‘heavy-brow’, on account of his prominent eyebrows). In spite of their own recent estrangement from the late emperor, the crusaders interpreted his deposition as a coup and characterised Murtzurphlus as a tyrannical usurper who must himself be removed from office. Girded by this cause for war, the Latins prepared for a full-scale assault on the great capital of Byzantium.

On 12 April 1204, thousands of western knights broke into the city and, in spite of their crusading vows, subjected its Christian population to a horrific three-day riot of violence, rape and plunder. In the course of this gruesome sack the glory of Constantinople was smashed, the city stripped of its greatest treasures–among them holy relics such as the Crown of Thorns and the head of John the Baptist. Doge Dandalo seized an imposing bronze statue of four horses and shipped it back to Venice, where it was gilded and erected above the entrance of St Mark’s Basilica as a totem of Venetian triumph. It remains within the church to this day.

The Fourth Crusaders never did sail on to Palestine. Instead they stayed in Constantinople, founding a new Latin empire, which they dubbed Romania. Aping Byzantine practice, its first sovereign, Baldwin, count of Flanders, donned the elaborate jewel-encrusted robes of imperial rule on 16 May 1204 and was anointed emperor in the monumental Basilica of St Sophia–the spiritual epicentre of Greek Orthodox Christianity. Across the Bosphorus Strait in Asia Minor, the surviving Greek aristocracy established their own empire in exile at Nicaea, awaiting revenge.

Causes and consequences

Contemporaries and modern commentators alike have been moved to ask what drove the Fourth Crusade to the ancient capital of the Byzantine Empire. It has been suggested that the diversion was the ultimate expression of a festering distrust and antipathy that had been an increasingly prominent characteristic of crusader–Byzantine relations during the twelfth century. After all, elements of the Second Crusade had considered attacking the Greek capital, and the Third Crusade had witnessed the forcible seizure of Cyprus, a Byzantine protectorate. Some have even intimated that the expedition was actually part of a complex anti-Greek conspiracy–that the seizure of Constantinople was the crusade’s deliberate and intended goal from the outset. This is unlikely to have been true–not least because the entire endeavour was characterised by such an evident lack of effective organisation.

In fact, the crusade was set on its course by the poorly framed 1201 treaty with Venice and almost certainly reached the walls of Constantinople through a succession of unplanned, pragmatic decisions and a series of cumulative diversions. There may not have been a grand design at work, but that is not to say that the Latins’ eventual bloody conquest of Constantinople did not suit Venetian interests or further the ambitions of some of the crusade’s leaders.

The expedition also confirmed the abject failure of Innocent III’s grand ‘papal crusade’ project. Events had shown that he was singularly unable to impose his will from Rome. In June 1203, when he first learned of the diversion to Constantinople, the pope had written to the crusade leaders explicitly forbidding any attack on the Christian metropolis, but this prohibition was ignored. Then, sometime before November 1204, Innocent received a letter from the new Latin Emperor Baldwin announcing the Byzantine capital’s capture. Baldwin’s missive evidently offered a heavily sanitised account of events, celebrating the conquest as a great triumph for Christendom and, despite his earlier misgivings, the Pope initially responded with jubilation. It seemed that, through God’s inimitable will, the eastern and western Churches now had gloriously been united under Roman rule, and that with the foundation of the new Latin polity fresh succour might be brought to the Levantine crusader states. Only later did details of the crusaders’ brutish avarice emerge, turning Innocent’s joy to disgust, prompting him to rescind his initial approval and condemn the expedition’s outcome as a disgraceful travesty.⁴

CONTROLLING THE FIRE

Innocent was appalled by the manner in which the Fourth Crusade spiralled out of control, but before long his innately pragmatic outlook and natural optimism prompted him to renew his interest in harnessing the power of holy war. In the course of the next decade, he repeatedly made attempts to utilise and control crusading. During this period, however, he redirected this weapon of papal policy towards new theatres of conflict and against different enemies. In part this was a response to emerging threats; thus, expeditions were launched against the pagan Livs of the Baltic and the Almohad Moors of Spain. And, despite his deep misgivings about the circumstances of its formation, Innocent also recognised that the newly formed empire of Latin Romania would need protection if it were to play any meaningful role in the wider struggle to recover the Holy Land. Other crusaders, therefore, were encouraged to reinforce Constantinople. The pope also concluded that crusades could play an important and direct role in his drive to purify western Europe itself. In 1209, he launched the so-called Albigensian Crusade against the Cathar heretics in south-eastern France, but the campaigns that followed proved to be shockingly brutal and largely ineffective, being subject to the self-serving acquisitiveness of northern French participants.

A popular outburst of ecstatic piety was witnessed in 1212, when, for reasons that remain uncertain (but may perhaps have been related to the preaching of the Albigensian Crusade), large groups of children and young adults in northern France and Germany spontaneously began to declare their dedication to the cause of the crusades. In the ‘Children’s Crusade’ that followed, two boys, a young French shepherd from Vendôme named Stephen of Cloyes and one Nicholas of Cologne, apparently raised hordes of young followers, promising that God would oversee their journey to the Levant and then lend them the miraculous power to overthrow Islam, recapture Jerusalem and recover the True Cross. As innocents, they claimed, children would be able to fulfil God’s divine purpose in a manner impossible for adults sullied by the taint of sin. Little reliable evidence survives regarding the fate of these ‘crusaders’, but for contemporaries then living in France, Germany and Italy–Innocent III included–their uprising served as a salutary reminder that the call of the cross could still move the hearts and minds of the masses.⁵