In 1308, when Duccio di Buoninsegna, the leading. painter in Siena during the late thirteenth and early fourteenth centuries, was hired to paint a Maesta (Virgin in Majesty) to replace the old altarpiece in the cathedral of Siena, his contract included the following provisions:

[He agrees] to make the said panel as even he was able . . . and to work continuously upon it at such times as he was able to work on it, and not to accept or receive any other work to be carried out until the said panel shall have been made and completed. . . . [Duccio is to be paid] sixteen soldi of Sienese money for each day that the said Duccio shall work with his own hands on the said panel except that if he should lose any part of the day there should be a deduction from...