In the year 1345, 22 members of the Ancient Guild of Pepperers founded a fraternity which in 1376 became known as the Worshipful Company of Grocers of London. The Pepperers Guild was first heard of in 1180, and to its members was entrusted the duty of garbling' or preventing the impairment of spices and drugs. They were also in charge of the King's Beam which weighed goods by the aver-do-poys weight, or "peso gross," and it seems likely that the Company derived its name from the medieval Latin "Grossarius" -- one who busy and sells in the gross.
Jean Bellamy provides additional details at Time Travel - Britain.
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