In the early Renaissance, artists were still organized into guilds, much like modern-day trade unions. To learn his craft, an artist would start as a teenager as an apprentice to a master painter in the master's workshop, where many artists worked together on the same painting. Following the apprenticeship (which might last as long as six years), the artist would be promoted to paid assistant until he finally became a master painter himself. The Church and nobility were the major patrons of the arts.
In Leonardo's day, artists were influenced by the humanist writings of Alberti and heeded his call to learn not only painting, but mathematics and science as well. In the course of this process, their status changed from trained craftsmen to gifted creators and thinkers.
