Cobalt blue
Cobalt blue in impure forms had long been used in Chinese porcelain, but it was independently discovered as a pure alumina-based pigment by Louis Jacques Thénard in 1802. Commercial production began in France in 1807. The first recorded use of "cobalt blue" as a color name in English was in 1777. The leading world manufacturer of cobalt blue in the 19th century was Benjamin Wegner's Norwegian company Blaafarveværket ("blue colour works" in Dano-Norwegian). Germany was also famous for production, especially the blue colour works ("Blaufarbenwerke") in the Ore Mountains of Saxony.
Violet budgerigar mutation
In Europe, the first mention of a bird which might have been a visual violet was by C af Enehjelm in 1935 in Copenhagen. In a letter to the Budgerigar Bulletin,
he said he had bred a Cobalt, "which I would call violet". In a later article
he gave full details of his violet birds, remarking that earlier birds he had seen which were bred in Germany in the late 1920s and marketed as violets were little different from normal Cobalts and lost their violet colour with age. His first true violet, mentioned above, was bred from an apparent dark green/blue cock obtained from a friend and a cobalt hen. This dark Green/blue cock was "very heavily suffused with blue (cobalt)". Presumably, it was in fact a SF Violet Light Green/blue.
He went on to breed several more Violets from the progeny of this bird.