ROYGBIV or Roy G. Biv is an acronym for the sequence of hues commonly described as making up a rainbow: red, orange, yellow, green, blue, indigo and violet. The initialism is sometimes referred to in reverse order, as VIBGYOR.
In Classical Antiquity, Aristotle claimed there was a scale of seven basic colors. In the Renaissance, several artists tried to establish a new sequence of up to seven primary colors from which all other colors could be mixed. In line with this artistic tradition, Sir Isaac Newton divided his color circle, which he constructed to explain additive color mixing, into seven colors. His color sequence including the tertiary color indigo is kept alive today by the Roy G. Biv mnemonic. Originally he used only five colors, but later he added orange and indigo to match the number of musical notes in the major scale.
The Munsell color system, the first formal color notation system (1905), names only five "principal hues": red, yellow, green, blue, and purple.
Another traditional mnemonic device has been to turn the initial letters of seven spectral colors into a sentence. In Britain the most common is "Richard Of York Gave Battle In Vain." The mnemonic is said to refer to the defeat and death of Richard, Duke of York at the Battle of Wakefield in 1460.
white, yellow, red, green, blue, purple and black