I can already here smart-pants saying, "you can write music with pencil on paper!", so yes, there is that. But how do you reproduce several prints of music, especially if you've come up with a masterpiece and want to share it with your town? Could you imagine handwriting 50 of the same compositions? ...what if the composition was several pages long?
Stumbling across a blog with a post about Music Printing in the Renaissance really opened my eyes to how things were done back in the day - it actually reminded me of my visit to Burnaby Village Museum during Christmas one year at the Burnaby Post. There they had a demonstration using a printing press, where individual letters and numbers (iron casted from a mold? i think?) were hand-placed into a contraption that allowed you to form words -sentences - paragraphs, then that contraption would be put into another place in the giant printing press -there it was lowered into ink and than stamped onto paper.
I found the video on the blog post to be really interesting and informative! And a quick watch as it's under 10 minutes. It's a refreshing history lesson, enjoy! :)