One day, British politician William Gladstone was reading through Homer’s Iliad when he realized he didn’t see the color blue mentioned at all. Homer famously described the sea as being “wine-dark,” but though he looked, Gladstone never found a comment about water or sky described as blue. So he decided to do an in-depth study of colors mentioned in the Homeric epics and discovered that Homer referenced black about 200 times and white around 100, but vibrant colors were mostly glossed over. Red, for instance, was mentioned less that 15 times and the word that describes both yellow and green less than 10. No mention of blue at all. Gladstone found the same results when he studied the Odyssey. In 1858, he published a book detailing his findings, and the academic world became intrigued.

Soon after Gladstone published his work, Lazarus Geiger decided to search other ancient Greek writings and found that the 6th century B.C. Greek philosopher Empedocles limited colors to four categories of white, black, red and yellow while Xenophanes, who lived during the same time, believed rainbows were only comprised of dark purple, a mixture of yellow and green, and red. Again, no blue. But the same phenomenon also applied to other cultures. While studying ancient literatures across the world, Geiger found no reference to the color in Icelandic sagas, the Quran, the Jewish Torah, Chinese literature or Hindu Vedas.

The only culture that did have a known word for “blue” were the Egyptians, who were both the first and only ancient civilization to create and use the color.

So why are there no references to blue in ancient texts? Some historians believe the Greeks (and everyone besides the Egyptians) literally hadn’t yet developed the capability to see blue. Yet others believe that because the color is so rare in nature, ancients had no need to name it. And since they had no name for it, they didn’t recognize it.

Sky image: p. Gordon

(h/t Business Insider)