The Worshipful Company of Goldsmith’s London assay office is where hallmarking in the United Kingdom originated more than 700 years ago.

Officially established in 1300 by a statute passed by King Edward I to test and mark gold and silver. The leopard’s head, known as the King’s mark, was adopted as the London assay mark. It is believed to have been taken from the royal arms.

The Goldsmith’s Company has an incredibly long, rich and fascinating history worth reading up on.