Etymolog
This expression was first used in the 6th century, in Saudi Arabia. Some attribute it to Abdilah Ibn Suhail. In that time, Saudi Arabia was known for its rhetoric widespread amongst the tribals. The expression appears to have surfaced in the 16th century, allegedly a literal translation of Plato's Republic. In 1545, William Turner wrote a version of the expression in the Rescuing of Romish Fox: "Byrdes of on kynde and color flok and flye allwayes together."