In the history of the Duomo di Milano, the 17th century was marked by debate regarding its façade. In fact, more than two centuries after its construction, the Duomo was still a complex and intricate construction site: the construction of the naves was approaching completion, but the façade of the ancient Basilica di Santa Maria Maggiore still stood between the third and the fourth aisles, by now incorporated in the longitudinal development of the new cathedral, and wouldn't be demolished until 1683.
Of utmost importance, after centuries of discussions about pillars, windows, capitels, tiburium, and vaults, the issue of which face, or rather which facade, to give the Duomo finally posed itself. The book by F. Repishti - R. Schofield Architettura e Controriforma (Architecture and the Counter-Reformation): the debates on the Duomo di Milano's façade, 1582-1682 (Milan 2003), carefully retraces the history of this crucial moment and the 37 important and articulate contributions that architects and experts submitted in favor of another solution are published. Among those called upon to express an opinion on the submitted designs was also Gian Lorenzo Bernini, of whom the Archives preserves a report written in 1652 (AS cart. 146, fasc. 17bis, n.10) and a print dated 1656. The two texts are incredibly different from one another, yet both are addressed to Cardinal Trivulzio, the Veneranda Fabbrica's representative for this delicate correspondence. The projects subjected to Bernini's evaluation were those of Carlo Buzzi and Francesco Castelli.
In this handwritten text, Bernini's evaluation favoured the proposal of Castelli: Because I like the façade designed by Mr. Castelli very much, as it embodies a style of architecture that can further enhance and glorify that which has already been constructed, I would ask (if it is permitted of me) that prior to the completion of such a famous and important project, Mr. Castelli kindly do another drawing in which he adds the belfries […] as I believe that in so doing he would demonstrate the superiority of his design.
Several years later, the same Bernini, once again called upon to express an opinion, had a much more bitter tone, given that the Fabbrica, despite his opinion and that of “several important professors of architecture of our time”, was proceeding with construction of Buzzi's design. However, this would not be the end of the long story of the Duomo di Milano's façade. It would be another three hundred years before one could say that it was finally concluded.