On the shores of ancient Tyre, fishermen waded into tidal pools to harvest Murex brandaris — a snail whose gland yielded, in sunlight and mineral baths, the deepest purple known to antiquity. Twelve thousand creatures produced a single gram of dyestuff, enough to tint one fold of an emperor's robe.
Purple as Legal Architecture
Silk was rare; cinnamon was rare; neither was reserved for the sovereign. Tyrian purple alone was entangled with legitimacy — Justinian's court codified which shades could adorn which body, and to wear the full purple unbidden was usurpation.
He who takes the murex without the Emperor’s seal has dressed himself not in cloth but in a claim upon the succession.
— Edict of the Chrysotriklinos, c. 880 ce