The most important legacy left by Datini is undoubtedly costuituita from his archive.
It represents a unique example of mercantile store full of all types of writings, particularly rich and studied mainly in the securities of the papers and specialized, now fully digitized and described computationally. This archive is a single source for the history of European mercantile world of the second half of the fourteenth century. It is kept at the State Archives of Prato, which is housed in the home of the merchant.