“Many modern flags that include green are those of Muslim countries, since the cloak and banner of Mohammed were said to be green, and in the Qur’an . . . the Blessed in Paradise were to wear green silk robes. A fourteenth-century Persian theologian, Alaoddwa Semanani, held that Mohammed himself was a shining green in his role as the Divine Centre, since this was the colour most appropriate to ‘the mystery of mysteries’.”

—John Gage, from Color in Art, 2006. Pictured is the national flag of Saudi Arabia. The Arabic text reads ‘There is no God, but Allah, and Mohammed is his Prophet.’