In ninth and tenth century Corneto (ancient name for modern Tarquinia) was fortified with the construction of surrounding walls in good part still visible today. Corneto then belonged to the Countess Matilda of Tuscany. According to tradition it was she who had built the fortress, which is visible at the end of the road heading south.

Every year, on a weekend of May, a traditional pageant of the medieval Joust of the Quarters is held at the Church of Santa Maria in Castello, in memory of the expulsion of the Moors who haunted the Italian coasts in the tenth century.