This is a section of the Cromwell Trial Plate used in the Trial of the Pyx in 1649. The Trial of the Pyx, still held every year in February, dates back to the 12th century; its purpose was to ensure, in a public demonstration, that coins produced at the Royal Mint were within set parameters surrounding weight, size and metallic composition. It is named after the box in which coins were transported, known as a pyx (from the Latin pyxis for box or chest – these were historically kept in the Chamber of the Pyx at Westminster Abbey), and involves melting down samples of coins and measuring the gold and silver content against a benchmark piece of metal known as a Trial Plate. This Trial Plate, created by the Goldsmith’s Company during the first year of the Commonwealth, is among 400 treasures on show as part of Gold: Power and Allure, a landmark exhibition celebrating the story of gold and Britain being held at the Goldsmiths’ Hall in association with the World Gold Council. Runs until 28th July. Admission is free. For more, head to www.thegoldsmiths.co.uk. PICTURE: © Royal Mint.