Richard of York Gave Battle In Vain

The Bosworth battlefield is one of the most iconic places in Physics as a result of the mnemonic for remembering the colours of the visible spectrum: Richard Of York Gave Battle In Vain. I liked the joke doing the rounds when the discovery of the remains of Richard the Third was announced: that physicists were renaming the colour violet as lilac so that it would read Richard Of York Got Buried In Leicester. The idea that there are actually seven colours is merely a convention. There are as many shades as you want. I read that Newton chose seven because the number had religious significance for him.