Purple owes its symbolism above all to the extreme cost of the ancient dye. Tyrian purple was extracted from the glands of murex sea snails on the Phoenician coast, and it took many thousands of the creatures to dye a single garment, making purple cloth literally worth more than its weight in gold and restricting it, under Roman and Byzantine sumptuary law, to the emperor and the highest ranks, to be born to the purple, porphyrogenitus, was to be born to one born a reigning emperor. From this material fact flows the whole later symbolism of purple as the colour of royalty, sovereignty and the highest authority, sacred and secular alike; a bishop's purple and a cardinal's red descend from these dye hierarchies.
Purple is also, in the Christian liturgy, the colour of Advent and Lent, penitence and preparation, and of mourning. Its association with the spiritual and the mystical, and in the modern chakra scheme with the crown centre, extends this long identification of purple with what is highest, whether in rank or in aspiration.