Joseph Deiss “My Hopper”

"For centuries the Phoenicians alone possessed the secret of the manufacture of purple. ... The Roman emperors transferred the manufacture of purple to Italy and conducted it as a monopoly. The art of purple dying, which, like many of the arts, had reached a high level at this time, was lost almost completely in the stormy period which marked the migration of nations. For a short time the art was still preserved in the Byzantine Empire, only to become extinct there in the 12th Century."

Josef Maria Eder, Edward Epstean, and Hinricus Lüppo-Cramer, HISTORY OF PHOTOGRAPHY. (New York: Columbia University Press, 1945).