Caligula's Daughter(1981)

Original title: A Filha de Calígula

Silvia, whose lover is a talking horse, is threatened by Scipio, her uncle and tutor, and by Marcus and Furius, advisers to the monarch, who aim to overthrow the daughter of the former Roman emperor. Scipio, as a strategy, wants to marry her to Marcus, but she refuses. The advisers, on the other hand, are simultaneously planning a coup against Scipio.