Giorgio Vasari, Lives of the Most Excellent Painters… (1850)
“ Agostino Chigi, being then called by certain of his affairs to Siena, took Giovan-Antonio with him, but while dwelling there, the artist, being a Knight without revenues, was compelled to set himself to work; he therefore painted a picture, the subject of which was Our Saviour Christ in the act of being taken from the cross; beneath is the Virgin in a swoon, with an armed warrior whose back is turned to the spectator, but the front of whose figure is shown as reflected from certain pieces of armour lying on the earth, and which armour is as clear as a mirror. ”
