Blue could also mean dark green, violet, black or brown. The ancient Greek word for a light blue, "glaukos", also could mean light green, grey, or yellow. The Greeks imported indigo dye from India, calling it indikon. They used Egyptian blue in the wall paintings of Knossos, in Crete, (2100 BC). It was not one of the four primary colours for Greek painting described by Pliny the Elder (red, yellow, black, and white), but nonetheless it was used as a background colour behind the friezes on Greek temples and to colour the beards of Greek statues. The Romans also imported indigo
Yellow-billed amazon work, "Systema Naturae". The yellow-billed amazon is long. Its plumage is mostly green with pink over the throat, upper breast and sides of neck, and blue in the larger wing feathers. Feathers over the ears are dark blue-green. The bare white eye-rings are surrounded by a narrow rim of white plumage, which continues as a narrow band of white over the forehead. Plumage over the lores is pale blue and the fore-crown is blue. A barred appearance over the back and sides of neck arises from the green feathers having black tips and edges. The tail feathers are green with