The Fourth Crusade and the Latin Empire of Constantinople
One of the most discreditable episodes in the history of the West is the Sack of Constantinople in 1204, writes Donald Nicol, when the leaders of the Fourth Crusade inflicted a savage punishment upon their Eastern brethren.
At the end of the twelfth century the relationships of Byzantium with the western world were complicated by mutual suspicions and conflicting claims. Three Crusades, and a long procession of pilgrims and adventurers to the east, had not contributed to the growth of understanding between Greeks and Latins.
The Crusaders who had with their own swords carved out principalities in Syria and Palestine were contemptuous of the more realistic attitude of the Byzantines towards the infidel. Peaceful coexistence with the enemy, which might have been achieved by Byzantine diplomacy, was mere defeatism to the Crusaders; and the recent victories of Saladin were attributed by the western world to the intrigues and treachery of the Byzantine Emperors.
Byzantium itself was torn between a policy of isolationism and the necessity of securing allies in the west. The Norman invasions of Greece were supported by the German Emperor Frederick Barbarossa; and his son, Henry VI, cherished ambitions for pursuing the Norman conquest to its logical conclusion, the destruction of Byzantium. In face of these threats, the Byzantine Emperors sought the friendship of Venice and the Papacy.