A preparatory study for the upper part of Saint Peter saved from the Water finished in 1628 in the Loggia della Benedizione in Saint Peter's, Rome. The fresco which replaced a painting by Bernardo Castello was one of Lanfranco's most celebrated compositions, and was copied by Trevisani, Ratti and Magnasco among others. Preparatory drawings for the fresco are at Naples and in the Louvre, E. Schleier, Disegni di Giovanni Lanfranco, Florence, 1983, nos. XXIVa-c, illustrated (with list of all preparatory drawings related to the composition) and R. Bacou and J. Bean, Le Dessin á Rome au XVII^e siècle, Paris, 1988, no. 87, illustrated