Vitruvius mentions the production of Tyrian purple from shellfish. Gospel manuscripts were written in gold lettering on parchment that was colored Tyrian purple. Only fine dyed tissues, like those made with Tyrian purple, were created in workshops. This dye is known as Tyrian purple. For those who could not afford genuine Tyrian purple, counterfeits were available. It was exploited from the "Murex trunculus" and "Murex brandaris" shellfishes, known as Tyrian purple. In ancient Rome, for example, only senators could wear garments dyed with Tyrian purple. This was the mollusc species used by the ancients to produce Tyrian purple fabric dye. He studied an incomplete ancient recipe for Tyrian purple recorded by Pliny the Elder. This tone of purple is bluer than the ancient Tyrian purple. Greek merchants established a Tyrian purple dye factory here. The dye was obtained from the Murex snail and was known as "Tyrian purple". Recent research in organic electronics has shown that Tyrian purple is an ambipolar organic semiconductor. The imperial robes of Roman emperors were of Tyrian purple trimmed in metallic gold thread. The deep, rich purple dye made from this snail became known as Tyrian purple.