i never laid eyes on francesco sforza until i was already dead to the world and a prowling vampire , but he was true to his descriptions , a man of heroic proportions and style , and believe it or not , it was to this bastard of a peasant and natural soldier that the weak-legged crazy duke of milan gave his own daughter in marriage , and this daughter , by the way , was not by the duke 's wife , poor thing , for she was locked up , but by his mistress .