Corrected entry: The stories of King Arthur take place in the Dark Ages, between 500-1000 AD. In the movie, lots and lots of people, mostly Arthur and his knights, wear blue clothes. Yet blue dye wasn't used in Europe until Marco Polo brought it from China in 1274, and even then it was extremely expensive.
J I Cohen
22nd Nov 2002
Correction: Woad was an extremely well-known blue dye, used for thousands of years in northern Europe (see http://www.botgard.ucla.edu/html/botanytextbooks/economicbotany/Isatis/). Far from being a rare and expensive colour, blue would have been one of the most common colours available.
J I Cohen