You might think they’re a bit unusual, but up until the 15th century yellow and white carrots were the norm. The orange variety didn’t crop up until the 1500′s.
According to the Carrot Museum (it does exist online and is very thorough) Dutch horticulturalists developed the orange variety by selective breeding. Apparently the yellow version was quite bitter. The orange variety is much sweeter, and higher in beta carotene. But it is also said that the orange carrot was cultivated by the Dutch to honour the House of Orange, their royal family. At the time William of Orange was king, he was a key figure in the Dutch revolt against the Spanish that eventually resulted in Dutch independence.
Regardless, the new Orange Carrot became the official vegetable of the House of Orange.
Interesting how something we almost take for granted today, is the result of what I guess could be centuries old Branding.