From Wikipedia (accessed 22/07/2013): Giovanni Antonio Boltraffio (or Beltraffio) (1466 or 1467– 1516) was an Italian painter of the High Renaissance from Lombardy, who worked in the studio of Leonardo da Vinci. Boltraffio and Bernardino Luini are the strongest artistic personalities to emerge from Leonardo's studio. According to Giorgio Vasari, he was of an aristocratic family and was born in Milan.
See more at: http://en.wikipedia.org/wiki/Giovanni_Antonio_Boltraffio
Painter of a vihuela (16-141)