Copyright Wonderings

Lately these days copyright issues have been occupying my mind quite a bit and this morning I got off onto a side track. When did copyright start up? Long, long ago (about the time I started school if you ask my students) an author would write a scroll and if you had a copy, purchased from or given by the author, you would commission a scribe to copy that scroll for you. Sometimes that commission's price would include letting the scribe make their own personal copy that they would then be able to make copies from. Unless you were buying from the original author none of that money ever made it back to the author. Author's were supported by a patron or their own personal finances.
It had to be sometime after the printing press was invented and the scribe evolved into the publisher. Now the author would take the book into the publisher and pay to have it published, the publisher would make multiple copies and either give them to the author to sell, or more commonly, sell them and send the author a share of the proceedings. Protecting this share must be the origin of copyright issues. How and why did this get turned around? What happened to build the 'system' we built today? I think this would be interesting to know. How did a bard's songs that were loved so much they were remembered and sung by the audience evolve to the mp3 copy of today? That would make an interesting show on the Discovery channel I would think.