He was a soldier, a statesman, and (as all good Doges were) a merchant, but he was humanly mindful of past injustices too.

Hence perhaps much of his eagerness to turn aside for Byzantium.
The plan was for the French to attack on the land; the Venetians on the sea.

Blind though he had become, Dandolo's memory of the harbour and fortifications enabled him to arrange the naval attack with the greatest skill, and he carried all before him, himself standing on the prow of a vessel waving the banner of S.Mark.The French on land had a less rapid victory, but they won, none the less, and the ex-king Isaac was liberated and crowned once more, with his son.

Both, however, instantly took to tyranny and luxurious excess, and when the time came for the promises of reward to be fulfilled nothing was done.

This led to the mortification and anger of the allies, who declared that unless they were paid they would take Constantinople for themselves.