At the end of February, 1562, Giorgio Vasari presented Cosimo I with the model for Palazzo della Carovana. In accordance with the principle with which the architect had rethought the whole square, the building was to use as fully as possible the older structure called Palazzo degli Anziani, respecting its pre-existing spaces while unifying them behind an elegant façade.
This solution was as technically difficult as it was financially advantageous: the Palazzo degli Anziani was inhomogeneous, composed of sections which were stylistically and chronologically different. In fact, it was composed of an older part on the right, called “palazzo vecchio”, dating from 1286, and a newer part on the left, called “palazzo nuovo”, dating from 1327, and these two parts themselves were composed of different structures. But Vasari quickly finished the main structural work and at the same time the new building of the loggia at the back of the building and of the side which now faces Via Consoli del Mare. The Knights could already move into their rooms by 1564, with the Grand Prior, given the importance of his position, occupying an apartment with various rooms.
The work was finished in 1567 but then continued again in 1577- 80 in the courtyard, where the kitchen and other service areas were connected to the main building via a portico.
Aspiring knights remained in the building for three years in order to receive an education in martial arts and in the sciences. The building was thus intended as a residence and place of study, functions which were taken up again when the Scuola Normale Superiore took its residence there in 1864.
This use can be seen in Vasari's choice of a sober and austere model for the interior, which conserved the lines of the medieval buildings. The knights reached their “quarters”, each formed of two rooms, by going through the triple loggia at the back of the building and climbing an internal staircase. This completely new staircase was the most impressive element of all, developing harmoniously on the second and third floors, opening into three flights; unfortunately, it no longer exists.
Vasari's intervention was above all in the ceilings: the ground floor rooms were completed with cross or circular vaults, while those on the upper floors were furnished with ordinary wooden ceilings, with the exception of the two larger rooms prepared for group activities: the Weapons Room—today called Sala Azzurra—and the Fencing Room—today called Salone degli Stemmi, on the second and third floors respectively, which were adorned with elegant panelled ceilings.