From this Fiſh [purpura in Latin] the Tyrians drevv a Liquor, vvith vvhich they dy'd Purple, and therefore it vvas call'd Tyrius color. This vvas in thoſe Days, vvhen they knevv no other VVay of dying this Colour, and therefore it vvas exceſſive dear, and only fit for the greateſt Perſons. Aftervvards the Scarlet Berries vvere found upon the Scarlet Oak, vvhich exceeded the Bevvty of the former Colour, and ſince then the VVeſt India Cochinille, has put dovvn both.
Source: wiktionary