If we are talking early early then it was because art wasn't a form of "art" it was a form of communication.
But a little later down the road, people did not understand the human body and could not paint one perfectly, and also painters loved to show perfection, as in, gold everywhere, or a kind a top a thousand bodies. Something like that. So yeah...
Anyone who knows to draw check my account on art post ! :)
A lot of pop music producers will start with a basic four-chord pattern, I–V–vi–IV. For example, if you are in the key of C Major, you would play a C Major chord (CEG), a G Major chord (GBD), a A minor chord (ACE), and an F Major chord (FAC). That is a popular "template" so to speak that can lay down the basic line for you to put other instruments over.
If you really want to get involved, a little bit of music theory never hurt anybody. You don't need to know much to get a basic understanding of the way things work.
I hope this helps :)
