the cathedral of S. Stefano, greater chapel]
... ho fatto una casa a Prato, di costo più che non vale il mio, ove è ordinato dai miei di là che tutti i Podestadi, tutt'i Fiorentini da bene, vi siano ricevuti, ben ch'io non vi sia, e per loro vi tengho parecchie onorate letta... ".
In this passage from the correspondence in 1400 between Ser Lapo Mazzei and Francesco di Marco Datini, the representative function that Palazzo Datini held for many years is well illustrated.
Ambassadors, cardinals, magistrates both Florentine and not and jurists were accommodated here when they visited Prato. Among the more significant names are Matteo d'Humières, ambassador to Charles VI of France (1393), Leonardo Dandolo, Venetian ambassador (1397), the Cardinal Pietro d'Ailly, Alexander V's chief penitentiary, who arrived with a retinue of fifty people "tra piè e cavallo" (1409), antipope John XXIII and King Louis d'Anjou (who stayed here twice in 1409 and 1410, on the second occasion, granting Datini the faculty to insert the gilded lily on an azure field in his own blazon).
The building was many times "lent" to the municipal authorities to organise the reception of particularly illustrious personnages, as happened with Francesco Gonzaga, Lord of Mantua, in 1392, when he arrived in the city to honour Cintola.