Roma: L'Antica Schiave dei Sensi (1984)

Roman emperor Caligula leaves the last days of glory amidst orgies of food and sex. During a show by two nude slaves, the emperor is particularly attracted to one of them, Lysia, ignoring that she had been planted close to him with orders to murder him. Only, the young man makes her feel for him, passion and motherly love, and she'll protect him rather then fulfill her mission. Drama ensues.