Bernini’s design, it is clear, was to be a much longer building that the Palazzo Cornaro, because there would be little space for the Trevi Fountain otherwise. From a document obtained from Lady Olimpia, two days before she bought the palazzo she received a brief from the Pope evicting the Gomez family from the smaller residence that adjoined the left part of her new home. Olimpia, in September of 1653, bought this residence to the right of her home as well, from two abbots. With the purchase of these two buildings, the façade becomes long enough to construct the envisioned design.
There is an important aspect of these purchases that confirms this design did actually exist. Since the purchase of the great palazzo was a mutual contract, the Lady Olimpia had more trouble with the palazzo alongside her home, and needed Innocent X to intervene on her behalf to fulfill her wishes.
Once the Pope learned that Lady Olimpia intended to enlarge her palazzo to improve and embellish the city, he issued edicts to evict the Gomez family, as well as the obstinate abbots. His demand was based upon the famous “Juris congrui “Constitution” of Gregory XIII”, which gave the Pope the right to expropriate any building he wished, including churches, convents, and monasteries, for the purpose of developing the city of Rome.
Therefore, since the Pope used the Gregorian Constitution to fulfill Olimpia’s wished, it has to be certain that she already had a design for the reconstruction of the three palazzi, that would be not only to her advantage, but also to the betterment of Rome, creating a more developed and beautiful city. For the hearing, an exhibit would have to be present with the design. And how do we justify the betterment of the city by enlarging a building with the two smaller adjacent buildings? We do this by creating an ornamental façade. And there is little doubt that had this design been built, it really would be a contribution to the elegance of the city.