The Temple of the Sibyl sits high atop a cliff overlooking the valley formed by the river Aniene. Built in the early 1st century B.C. on a circular plan, the temple was once ringed by eighteen Corinthian columns, of which only ten remain. In the Middle Ages, it served as a church, which purpose ensured its survival. John Warwick Smith was a topographical artist sent by the Earl of Warwick (from whom he derived his pseudonym) to travel and sketch in Italy from 1776 to 1781.