Tyrian purple by ancient authors. Not much is known about the subsequent steps, and the actual ancient method for mass-producing the two murex dyes has not yet been successfully reconstructed; this special "blackish clotted blood" colour, which was prized above all others, is believed to be achieved by double-dipping the cloth, once in the indigo dye of "H. trunculus" and once in the purple-red dye of "B. brandaris". The Roman mythographer Julius Pollux, writing in the 2nd century AD, asserted ("Onomasticon" I, 45–49) that the purple dye was first discovered by the philosopher Heracles of Tyre, or rather, by his dog, whose
HMS Tyrian (R67) and ratings. The ship was armed with four 45-calibre 4.7-inch (120 mm) Mark XII guns in dual-purpose mounts. For anti-aircraft (AA) defence, "Tyrian" had one twin mount for Bofors 40 mm guns and four twin Oerlikon autocannon. She was fitted with two above-water quadruple mounts for torpedoes. Two depth charge rails and four throwers were fitted for which 70 depth charges were provided. Between 1946 and 1951 "Tyrian" was held in reserve at Harwich. Between 1951 and 1952 she was converted to a Type 16 fast anti-submarine frigate, by Harland & Wolff at Liverpool. She was also allocated the new