Exchequer: King's Remembrancer: Records Relating to Trials of the Pyx

Coinage is produced to standards of weight and composition prescribed by law under the Coinage Acts. In order to ascertain that coins issued from the Mint have been coined in accordance with these acts, the master or deputy master is required to set aside prescribed numbers of coins from each day's work for submission to a public trial, known as the Trial of the Pyx. The 'pyx' is the box or chest in which these coins are placed.

Though held since the middle of the 13th century, the trial received no statutory recognition until the Coinage Act of 1870, which laid down in great detail the rules for its conduct. The act provided that the trial should be held annually and that a jury of the Goldsmiths' Company, which since the reign of James I (1603-25) had assisted at the trial, should be summoned as assessors. By an Order in Council of 29 June 1871 the preliminaries of the trial were removed to Goldsmiths Hall, the presidency was transferred from the lord chancellor to the Queen's Remembrancer, the Treasury was required to fix the date, and the Standards Department of the Board of Trade to provide future trial plates of coinage composition and to produce them with a set of the standard weights at the trial. The ancient trial plates were held by the Exchequer in a chapel of Westminster Abbey known as the Pyx Chapel, until they were transferred to the Mint in 1843.