The name Guido is known from the large panel in the church of San Domenico, Siena of the Virgin and Child Enthroned.
The rhymed Latin inscription gives the painter's name as Guido de Senis, with the date 1221.
The faces of the Virgin and Child were scraped and repainted in the early 14th century in the manner of Duccio and so are not representative of Guido's original.
7) in the Siena Pinacoteca has an identical inscription, but unfortunately the name before "de Senis" has been cut off.
It is very often assumed that the missing name is Guido, and gives us some indication of the original appearance of the Madonna at San Domenico.