Giorgio Vasari, Lives of the Most Excellent Painters… (1850)
“ Gentile had been no long time in Constantinople before he portrayed the Emperor Mahomet from the life, and so exactly, that it was considered a miracle. Then the Sultan, after having seen many proofs of his ability in that art, desired to know if the painter had courage to take his own likeness? to which Gentile having replied that he had, many days had not elapsed before he had portrayed his own features, with the help of a mirror, so faithfully that the picture seemed to be alive. ”
