Pozzo di San Patrizio

The Pozzo di San Patrizio is a historic well in Orvieto, Umbria, central Italy. The city is high on the flat summit of a large butte of volcanic tuff that was fortified with defensive walls. The well was built between 1527 and 1537 by the architect-engineer Antonio da Sangallo the Younger of Florence, at the behest of Pope Clement VII who had taken refuge at Orvieto during the sack of Rome in 1527 by the Holy Roman Emperor Charles V. The city proved to be an excellent refuge except that Clement feared that the natural water supply for Orviieto would be insufficient in the event of a protracted siege. The well was completed in 1537 during the papacy of Pope Paul III.

The name was inspired by medieval legends that St. Patrick's Purgatory in Ireland gave access down to Purgatory, indicating something very deep.