There are not many information about the origins of the Palace; what we know is due to the big fresco in the Frescoes Hall. An Angel that puts together with an olive branch 2 Families: Ciacci and Palagi. But for something strange there was not any marriage.
Mr Palagi decides to stay alone with his 14 lands and at his death he left all his properties to the sons of the waitress that lived in the palace without creating their own family. When one of them died, only one was the owner of the building, making Palazzo San Niccolò the house of his cats.