Halfway down the nave one can descend into the crypt via a double stairway. This burial place of Saint Francis was found in 1818. His remains had been hidden by Brother Elias to prevent the spread of his relics in medieval Europe, a story told by Jon M. Sweeney in "The Enthusiast". By order of Pope Pius VII a crypt was built under the lower basilica. It was designed by Pasquale Belli with precious marble in neo-classical style. But it was redesigned in bare stone in neo-Romanesque style by Ugo Tarchi between 1925 and 1932.