It is one of the most representative of the entire region, built at the beginning of the eleventh century by Elia. This basilica has been cited, among others, by Pope Gregory VII in 1076, by Alexander III in 1176, by Innocent III in 1211. In 1740 this Basilica entered a period of decline due to the opening of the new Church of Saint Anthony when under the pontificate of Pope Pius IX. St Elijah is a Romanesque basilica with three naves and a transept contained in a lopsided rectangle. The apse is entirely frescoed with paintings executed during the eleventh century and are among the most interesting and best preserved in the Romanesque churches of Lazio.