Leonardo's father, Ser Piero, realising that his son's talents were extraordinary, took some of his drawings to show his friend, Andrea del Verrocchio, who ran one of the largest artists' workshops in Florence. Leonardo was accepted for apprenticeship and "soon proved himself a first class geometrician". Vasari says that during his youth Leonardo made a number of clay heads of smiling women and children from which casts were still being made and sold by the workshop some 80 years later. Among his earliest significant known paintings are the "Annunciation" in the Uffizi, the angel that he painted as a collaboration with Verrocchio in "The Baptism of Christ", and a small predella of the "Annunciation" to go beneath an altarpiece by Lorenzo di Credi. The little predella picture is probably the earliest.