Did you know that carrots were not originally orange?  Carrots were generally purple or yellow, orange being an uncommon mutant variety, until the 16th Century, when breeders in the Netherlands stabilised and improved the taste and cultivation of the orange variety.

It appears to be a myth that they did so as a tribute to William of Orange, but it is a nice coincidence that the Dutch developed the orange carrot, their royal family is the House Of Orange, and their national colour is orange.