remarkable incident took place. Raphael had painted a celebrated
portrait of Pope Leo X. in a group, and the picture belonged to
Ottaviano de Medici. Duke Frederick II., of Mantua, longed to own this
picture, and at last requested the Medici to give it to him. The Duke
could not well be refused, but Ottaviano wanted to keep so great a
work for himself. What was to be done? He was in great trouble over
the affair. The situation seemed hopeless. It seemed certain that he
must part with his beloved picture to the Duke of Mantua; but one day
Andrea del Sarto declared that he could make a copy of it that even
Raphael himself could not tell from his original. Ottaviano could
scarcely believe this, but he begged Andrea to set about it, hoping
that it might be true.

Going at the work in good earnest, Andrea painted a copy so exact that
the pupil of Raphael, who had more or less to do with the original
picture, could not tell which was which when he was asked to
choose. This pupil, Giulio Romano, was so familiar with every stroke
of Raphael's that if he were deceived surely any one might be; so the
replica was given to the Duke of Mantua, who never found out the
difference.

Years afterward Giulio Romano showed the picture to Vasari, believing
it to be the original Raphael, neither Andrea nor the Medici having
told Romano the truth. But Vasari, who knew the whole story, declared
to Romano that what he showed him was but a copy. Romano would not
believe it, but Vasari told him that he would find upon the canvas a
certain mark, known to be Andrea's. Romano looked, and behold, the
original Raphael became a del Sarto! The original picture hangs in the
Pitti Palace, while the copy made by Andrea is in the Naples Gallery.