Mediterranean royal purple: Biology through ritual

The eastern Mediterranean coast was the center of the dyeing industry in the ancient world. Royal purple, the most famous indigoid dye of antiquity, was derived from hypobranchial-gland extracts of various marine gastropod mollusks. Extensive marine biological surveys have revealed that the only snails in the Mediterranean that produce stable dyes are those of the murex family. The dye obtained from the common snail Murex trunculus is very stable and steadfast. The extracts were processed in a lengthy, elaborate procedure, according to the Roman writer of the first century AD, Pliny the Elder; other, more cursory texts are known from the Classical Greek period up until Byzantine times. Purple dyeing was also discovered by cultures on the western and eastern shores of the Pacific Ocean in China and Peru, respectively, apparently with no connection to the Canaanites or Phoenicians. We describe here the history of this dye from its earliest traces, through its role in Jewish rituals, its rise to Roman regal attire, and its subsequent decline and final replacement by synthetic products.