Danny Kaye vs. Basil Rathbone in The Court Jester

The 1955 movie The Court Jester is remembered for its tongue twister "The pellet with the poison's in the vessel with the pestle; the chalice from the palace has the brew that is true!" (see that here) but also for the climactic sword fight between Hubert Hawkins (Danny Kaye) and Lord Ravenhurst (Basil Rathbone). Our hero (Kaye) is doing okay but is frightened until he gets hypnotized and the action gets even more chaotic. Basil Rathbone was a fencing champion from his army days, and taught swordmanship to Errol Flynn. He also taught Kaye to fence for this film. So why did he use a double for most of this fight scene? Who knows- maybe it's because he was in his 60s by then and didn't want to spend weeks fighting to film it. (Thanks, WTM!)