How did golf caddies get their name?

When Mary, later Queen of Scots, went to France as a young girl (for education and survival), Louis, King of France, learned that she loved the Scot game of golf. So he had the first golf course outside of Scotland built for her enjoyment.

To make sure that she was properly chaperoned (and guarded) while she played, Louis hired cadets from a military school to accompany her. Mary liked this, and when she returned to Scotland (not a very good idea in the long run), she took the practice with her. In French the word cadet is pronounced "ca-day" and the Scots changed it into "caddie."