In the ancient world, purple was the most expensive and sought-after color for clothing, becoming a symbol of power and royalty. This 'Tyrian Purple' was produced by the Phoenicians in the cities of Tyre and Sidon. The dye was extracted from the mucus of thousands of tiny predatory sea snails known as Bolinus brandaris (Murex). It took approximately 10,000 snails to produce just one gram of dye, making the pigment worth more than its weight in gold. The process was not only labor-intensive but also famously foul-smelling, leading dye-works to be located far from city centers. Because the dye bound chemically to the fabric rather than just coating it, the color actually became more vivid and bright with exposure to sunlight and washing. Roman emperors eventually passed laws (sumptuary laws) that restricted the wearing of purple to the imperial family alone.