The project to equip the ancient hospital with an “open gallery” on the square started in XVI century but stopped abruptly in 1571 when the works were just started: actually were paid Master Romualdo da Settignano for having provided five drawings of the factory that was going to be built, and some bricklayers. So the works did not have an immediate continuation and the open gallery’s foundations were laid only on 2 December 1604 by Master Giovanni Antonio Lombardo, who finished the construction in 1609. It is not possible to say whether the building construction followed the older project by Master Romualdo; however it follows the most traditional arrangement of the Tuscan hospitals, with a clear reference to the famous open gallery of the Spedale degli Innocenti in Florence.

Together with this open gallery was also built another one on the first floor facing the square and it can remembered today only by the historical photos [1, 2] because it was completely destroyed at the end of the 19^th century when the complex was sold to private people. The widening of the other side of the open gallery, for which the famous architect Gherardo Silvani provided the design, goes back to 1660.