This article reconsiders the role of Palladio's friend and patron the Venetian Senator Marc'Antonio Barbaro in the design of the church of the Redentore in Venice, commissioned after the great plague of 1575-76. It examines the circumstances surrounding Barbaro's unsuccessful support of the centrally planned design in light of his recent return from a five-year period as consul in Constantinople. The religious and political issues informing the debate are investigated in detail, in order to amplify the motives behind the final choice of plan. The architectural dialogue between Venice and Milan, two cities seeking to build votive churches after the plague, forms one axis of the debate, but Venice characteristically looked east as well as west. The article suggests that Palladio's subtle range of allusions may have included not only the lessons of antiquity and issues of church reform, but also ideas drawn from the recent work of the great Ottoman architect Sinan. Significantly, Barbaro's dispatches from Constantinople had transmitted enthusiastic descriptions of new Ottoman buildings to the heart of the Venetian Senate.

In 1949, Wittkower proposed that musical harmonic ratios were a principle underlying Palladio's designs illustrated in the ground plans of Book II of the Quattro libri. This theory, expounded in Part IV of Wittkower's Architectural Principles in the Age of Humanism, has been widely accepted, despite the fact that his research was based on detailed analysis of only 8 of the 44 plans in Book II. In the present study, a systematic, quantitative analysis of all the plans in Book II of the Quattro libri is carried out to discover to what extent musical harmonic ratios were an important principle behind Palladio's ground plans. Our results show that Palladio did indeed have a definite preference for numbers which can be related in ratios corresponding to the standard musical intervals. However, he does not make any consistent attempt to render his designs completely harmonic. Only about two-thirds of all the dimensions in the Book II plans are numbers which can be incorporated into musical ratios. Palladio often made no attempt to make his published measurements accord with musical harmonies where this could have been done by minor alterations, such as insignificant changes in wall thicknesses. The actual buildings, too, show a preference for dimensions which can be related by harmonic ratios, although not quite to the extent of the plans published in the Quattro libri. A few, most notably the Villa Barbaro at Maser, are significantly more "harmonic" in the published versions than in reality. In view of Daniele Barbaro's well-known interest in harmonic proportion, it is significant that all the completely harmonic designs postdate Palladio's collaboration with Barbaro on the Vitruvius edition and the Villa at Maser. Most of the patrons of those designs closely based upon musical harmonies appear to have shared an interest in musical or architectural theory. While Palladio almost certainly used musical theory in some later designs, his dependence on musical harmonic proportion was by no means as great as Wittkower implied. Elsewhere, his preference for harmonic dimensions probably resulted either from his use of certain favorite room shapes, or from the practical advantages of using simple, easily divisible numbers.