As a result of the intrigues connected with the Fifth Crusade, in which crusaders and Venetians—­the latter for their own commercial advantage—­jointly participated, it was decided to capture Constantinople, the seat of the Byzantine empire, and to partition the empire itself among the captors.  The combined forces of the Latins accordingly made two assaults upon the capital of their Eastern fellow-Christians, who had from the first made passive opposition to the crusades, fearing for the integrity of their empire.  The city succumbed to the second attack and was thoroughly plundered.  The division of the empire was especially insisted upon by Dandolo, the aged doge, who led the Venetians in the expedition.

The Venetians well knew that whoever held the city of Constantinople held the key of the East.  It proved in the end that they had an imperfect knowledge of the strength and resources, as well as of the peculiar weakness, of the Byzantine possessions, which at best were but loosely held together, and required ceaseless vigilance on the part of the central government to guard them against outward attack and hold in check the spirit of internal revolt.

It was nevertheless the cautious policy of the Venetians not to hold the key of the East, Constantinople, since to hold it would entail the necessity of defending its possessions.  They preferred to be on such terms of friendship, not necessarily alliance, with those who should hold the key, as would give them all the advantages they desired, without involving them in irksome obligations if there came a change of masters.  “Venice fought for her own hand,” let other nations as they might be led astray by illusory hopes of allies and friends bound by ties of gratitude.  She well knew how to guard herself against the spirit of perfidy so active in the Middle Ages, as well as how to exercise that spirit in her own interest.

Once in possession and control of Constantinople, the Latins found it necessary to proceed directly to the partition of the empire.  It had been agreed between old Dandolo and Baldwin, Boniface and others of the crusaders that one full quarter of the whole dominion was to be assigned to the Latin emperor, who was to be elected by Venetians and crusaders together.  This left three-quarters remaining, of which Venice was to take half, the rest to be in some manner divided among the crusaders.  First of all, however, came the election of an emperor for the new state.

Venice wanted no imperial dignity, nor could any dignity be bestowed upon the nonagenarian Dandolo greater than that which he actually enjoyed as doge of his native republic.  He accepted, however, the title of Despot of Romania.[50] The emperor must therefore be chosen from among the French or Flemings.  Two of the chiefs might show strong claims for the choice.  Of these two, the Marquis of Montferrat, who at first seemed the most likely to be chosen, was already connected by means of his brother’s marriage with the late reigning dynasty of Constantinople.  He was, besides, proved to be a valorous soldier and a prudent general.  On the other hand, Baldwin, the count of Flanders, a younger man, had displayed all the prowess of his rival, and was personally more popular.  Besides, the larger part of the army consisted of his own people, Flemings.