This is a print on demand publication. Born in 1698, Della Valle came to Rome in 1725 upon the death of his master, Giovanni Foggini. There he remained until his death in 1768. The phrase "passive tranquillity" refers both to the style of Della Valle's sculpture & the ambiance of 18th-cent. Rome, &, further, serves to distinguish Della Valle from his better known precursors, Gianlorenzo Bernini & Michelangelo. Theirs was a sculpture of the heroic & expressive. Della Valle's sculpture represents figures of an introverted, serene type. In its demonstrations of the ways in which Della Valle's art could have been formed by the institutions & cultural currents of 18th-cent. Rome, the text seeks to account for that sense of quiescence & composure common to the arts of settecento Rome. Illustrations.