What are you, blind!?

Explanation: During the religiously motivated 4th Crusade, the Catholic Western Europeans ended up besieging and sacking their fellow Christians (though of a different sect) in Constantinople of the Byzantine Empire. One of the notable financiers of the crusade was Doge Enrico Dandolo of Venice, who was blind at this point. Other than Venice being the long-term enemy of the Byzantine Empire, by some accounts Doge Enrico Dandolo had been literally blinded by the Byzantines after a failed Venetian raid.

… he was an enthusiastic supporter of the ‘detour’ to ruin one of his polity’s traditional enemies and fill his pockets with loot in the process.