I suppose most of us don't consider how fortunate we are to be artists in a time when there are so few limitations imposed upon us from the outside world in terms of what we paint and how we paint it. In fact, it is this lack of limitations that causes some of us to kind of float around in a sea of chronic indecision as to who, what, and where we are in art. We need limitations so much sometimes that we impose them upon ourselves, or seek those who will impose them upon us (as in accepting a commission). Thus, it's hard for us to imagine a time when if we chose to become an artist (or were chosen to become an artist), we had but one patron (the church) and thus one area of subject matter (religious), and one style (Medieval) in which render the images that were mostly imposed upon us from above by whatever religious despot happened to be in charge at the moment. This is the world of the young Giotto di Bondone.
Legend has it that the boy was born to peasant shepherds in 1266 near Vespignano, Tuscany, not far from Florence. As a lad of ten or twelve, he amused himself while watching the family sheep by drawing them on flat rocks with charred sticks (basically a crude form of charcoal). A passing stranger one day watched the boy drawing and recognised genius when he saw it. He persuaded the boy's father to let him become an artist and in so doing, lifted the entire family from poverty to fame and fortune. In reality the story more likely involved a scout for the painting master, Cimabue, having heard about the boy's skill, checked out his meagre efforts, and arranged an apprenticeship. The fame and fortune part is quite true for the work of this talented young Florentine, over the course of the next seventy years, paved the way for painting to emerge from the mosaic-like quality of the Medieval period to the Naturalism of the Renaissance.
When a young boy became an apprentice (and only young boys became apprentices at this point in time), the transaction more closely resembled his being purchased than educated, for the life he would know for the next dozen years or so would more closely resemble slavery than training, especially in early years. Apprentices, and sometimes there were dozens of them, working in their master's household, started out by doing the dirtiest, most menial jobs imaginable, having nothing whatsoever to do with art. Gradually they worked up to the menial painting tasks of grinding pigments and preparing plastered walls (Cimabue did frescos) only as still younger boys came on board. If he was talented and fawning enough, the apprentice might get to work along side the master or even in place of him on important church commissions. If he were Giotto, he would, in those dozen or so years, come to surpass his master and take on apprentices of his own.