Trial of the Pyx

Coins were to be put into a box with two keys, each held by the master and warden and its contents tested four times a year.

[2] In 1282, in the reign of Edward I, a writ was issued ordering barons to carry out pyx trials throughout the realm.

It is his or her responsibility to ensure that the trial be held in accordance with the law and to deliver the jury's final verdict to His Majesty's Treasury.

The Deputy Master of the Mint must, throughout the year, randomly select several thousand sample coins and place them aside for the Trial.

Sitting along a table, the jurors are handed packets of up to 50 coins, by a Royal Mint official, which they must count.

[9] If the coinage is found to be substandard, the trial carries a punishment for the Master of the Mint of a fine, removal from office, or imprisonment.

The last master of the mint to be punished was Isaac Newton in 1696,[1] though he later showed that the mistake originated in a faulty reference.