Most art during the Renaissance period was done by commission. A patron came to the artist and told them what it was that they wanted, and all aspects of the transaction were hashed out ahead of any actual creative work being done: pay, time to complete the work, what medium would be used, and the subject of the work. A Renaissance era artist had the advantage of knowing ahead of time all he would need to complete such work, at the disadvantage of very little artistic license. More modern artists, mostly working for their own benefit and with their own creative drive powering their work, must work absent this same "patronage", and create what is popular or likely to sell and assign a value to their own work based on prevailing market value and demand.
