Before there were what we know as Universities, artists of all kinds learned their trades through apprenticeships. Even the great artists had teachers; Michelangelo had Ghirlandaio who taught him fresco and even Leonardo Da Vinci was apprenticed to Andrea Del Verrochio. In the painting “The Baptism of Christ” Verrocchio let Leonardo paint the angel in the lower, left corner. The results are amazing. It’s obvious that the angel is painted by someone more apt than Vercocchio. The face is truly angelic, the hair looks as though it would be soft and fine and the fabrics… few people rendered fabrics like Da Vinci.
Leonardo was in his early 20s at the time and Vercocchio was so astonished by his pupil’s talent he vowed to never paint again and spent most of his remaining career sculpting. This anecdote is apocryphal, but I know that if I had a student whose talent outshone mine like this I’d probably be pretty frustrated too!!