In the 9th century (about 1300 years ago) The Banu Musa brothers in Baghdad invented an automatic organ and flute player that played a lot like a player piano or music box (invented in 1796). The player piano used paper scrolls in 1876. Did that count as DJing? I would argue that they were, because they were using pre-recorded music to entertain an audience. While the techniques have definitely improved since then, the rules are still the same - make people dance!