Mazzeo della Montagna appears in ’s fourth tale (IV, 10). Based on a historical, 14th-century physician, Mazzeo is a respected doctor who marries a young and beautiful woman (), whom he is subsequently unable to satisfy sexually. Thus, along with , , and , he exemplifies the stereotypical medieval character of the senex amans (old lover). Further, he demonstrates a cavalier attitude towards the sexual mores of the lower-class members of his household, forgiving the for an affair he wouldn’t have been happy to discover his wife conducting with .