Enrico DandoloEnrico Dandolo was the Doge (1192-1205) of Venice during the Fourth Crusade.
He was old (at least in his late seventies when he became Doge), and blind, but displayed tremendous physical and mental strength. He persuaded the Crusaders to help him capture Zara in return for naval transportation to the Kingdom of Jerusalem, as well as forgivement of debts they had run up while waiting for passage from Venice.
Following the capture and sack of Zara (November 15, 1202), Alexius arrived in that city, and with Dandolo's help, convinced the crusaders to restore him to the throne of the Byzantine Empire. This led to the eventual sack of Constantinople on April 12, 1204, at which event Dandolo played a direct role.
He was active enough to take part in an expedition against the Bulgars, but died in 1205. He was buried in Hagia Sofia in Constantinople; his grave is still visible there today, though it is quite small and easy to miss.