I recently read a biography about William Shakespeare (though it was more an account of how little we actually know about him), and in it they say that none of his manuscripts was found among his personal effects at the time of his death because, at that time, the owners of the theaters that put on the plays actually owned the plays themselves. The writers just received a relatively meager, one-time fee and handed over their written work.
Now, I know the printing press had been invented already, but there were no printers or copying machines. I never would've been able to write more than, like, three plays in my entire life if I lived back then because my borderline OCD would've required me to hand copy several copies of everything I wrote for fear that the theater company might lose the original, or the lone copy might get stolen, etc... I would've spent the bulk of my existence copying down what I'd already written!