Commentary Par VI 40-42

Dante (Conv.IV.v.11) includes three Tarquins among the first seven kings of Rome: ' ... the seven kings who first governed her -- namely Romulus, Numa, Tullus, Ancus, and the Tarquin kings who were the rulers and the tutors, so to speak, of her youth' (tr. R. Lansing).  That means Dante counts the sixth king, Tullius Servius, related by marriage but not by birth, as one of the Tarquins, as Toynbee explains (Tarquinii).

It is probably significant that the first period of Roman history is marked, at either end, by rape, that of the Sabine women in Romulus's rule, and that of Lucrece by her husband's cousin, Sextus Tarquinius, son of Lucius Tarquinius Superbus, seventh king of Rome.  That second act of sexual violence eventually had the result of ending Tarquin rule (510 B.C.).