 In circa 1454 pope Nicholas V commissioned building a bath palace in Viterbo, and the construction at the "Bagno del Papa" was continued on through the reigns of several popes after Nicholas V. The Vatican accounts mention of payments "for building done at the bath palace of Viterbo" during the reigns of Calixtus III, Paul II, and Sixtus IV.There also is evidence Pope Pius II was responsible for the addition of a western wing to the building.Contrary to popular belief bathing and sanitation were not lost in Europe with the collapse of the Roman Empire.