Sack of Constantinople

Constantinople

The ancient city of Constantinople is known today as Istanbul, located in modern-day Turkey. Its location between Asia and Europe and its natural harbour meant that geographically it had many advantages; Constantinople's trading port thrived because of this. Founded in 330 AD, this successful and powerful city was once the capital of the Roman Empire, the Latin Empire, and the Ottoman Empire!

Fig. 1 - Constantinople in Byzantine times

Siege of Constantinople

The Fourth Crusade (1202-1204) was just one in a series of religious campaigns to recapture Jerusalem.

Nonetheless, the many years of fighting since the First Crusade in 1095 had led to economic issues all around Europe. The monarchs of Europe refused to engage in another crusade due to their depleted finances. As a result, an Italian aristocrat named Marquis Boniface of Montferrat took over the leadership of the crusade.

Despite the financial strain of the Crusades, the Kingdom of Venice demanded the 240 ships they had afforded for the crusade to be paid with 85,000 silver marks. This sum was double the amount of France's yearly income at the time! The demand spelt out the fragile European economy that drove the crusaders to view the crusades as a way to gain money rather than recapture a centre of spiritual importance.

Fig. 2 - Venetian ships attacking Constantinople

Unable to pay such a hefty price, the crusaders made a deal with the Venetians. The crusaders would attack Zara with the 50 warships provided by the Venetians in return for half of the territory claimed during the crusade. Once news got out of the sack of Zara, the Pope excommunicated the Venetians and Crusaders as Zara was a Christian City. This ex-communication lasted only briefly, as the Pope needed these groups to strengthen his crusade.

Sack of Constantinople Timeline

The conflict and betrayal that stretched across two years (1202-1204) saw many casualties, crimes and crucial changes for the Byzantine Empire. The table below highlights the most important key dates to know during this period of conflict!

Conquest of Constantinople

A essential factor in the eventual siege and fall of Constantinople was the distrusting relations between the Christians of the East and the West. The Byzantines never fully accepted the concept of a Holy War, which they saw as degrading to the noble nature of Christianity. They essentially viewed the Western crusaders as an unruly mob of looters and rapists (acts which, to the embarrassment of the Western Church, they did engage in).

On the other hand, the West believed that the Byzantine Emperors were indifferent to the Crusades and merely wanted to preserve their Empire and the status of Constantinople as the largest and most glorious Christian city. The mistrust carried well into the 13^th century and played a crucial role in the decision of the Western crusaders to attack Constantinople.

Fig. 3 The Byzantine Empire Map 1020

The objective of the crusaders had been Jerusalem from the start. So what changed?

Doge Enrico's previous expulsion from Constantinople while acting as Venetian ambassador left a residue of bitterness. And so, in his determination to secure domination of trade for the Venetians throughout the East, his actions were less than noble. Doge Enrico formed a secret deal with Alexios IV Angelos, who had been deposed in 1195.

Enrico believed that by placing Alexios on the Byzantine Empire's throne, the Venetians would have access to better trading opportunities than their enemies: Pisa and Genoa. Some crusaders favoured the security of Papal supremacy that this would give over the Eastern church. In contrast, others were interested in the wealth of Constantinople. The consequences of these plans meant that the crusaders could seize Jerusalem with increased financial capacity.

Fall of Constantinople

On 24 June 1203, the crusaders arrived at Constantinople, bringing an impressive force of around 30,000 Venetians, over 14,000 infantrymen and a total of 4,500 knights! With this large force, they attacked Byzantine garrisons near Galata, catching Emperor Alexios III Angelos by surprise and resulting in his fleeing from the city.

Having secured the people's and the army's support, Alexios V Doukas, a commander and senior diplomat, usurped the throne from the incumbent Emperor Alexios III Angelos by staging a palace coup. To kill his predecessors, Alexios V Doukas had Alexios IV and Isaac II executed in January 1204. Alexios V promised to defend the city. He strengthened the Theodosian Walls and initiated raids on crusader camps to weaken them. These military efforts made him popular, yet later proved ineffective against the crusaders.

Fig. 4 The Byzantine Emperor Alexios V Doukas

Battle of Constantinople

The crusaders overwhelmed the walls of the city. Once they had overcome the Byzantine garrison at Galata, they could lower the chain blocking access to the harbour at Golden Horn. After this, the crusaders steered their fleet toward the sea and land defences of the city simultaneously. The attack was so overwhelming that even the Varangian Guard could not prevent the fall of Constantinople.

Consequences of the Sack of Constantinople

Following the Sack of Constantinople, the Byzantine Empire was weakened and distributed among Venice and its allies. The table below outlines the resulting gains of this agreement that followed the instructions of the 1204 Partitio Romaniae treaty.

Count Baldwin of Flanders was crowned on 9 May 1204 as the first Latin Emperor of Constantinople. Many Byzantines refused to recognise Flanders as their leader, and the empire was fragmented into four separate conflicting states. The Byzantine Empire would not be re-established until 1261, under Emperor Michael VIII.