The vast majority of English, Scottish and Irish silver produced in the last 500 years is stamped with either four or five symbols, known as hallmarks. The prime purpose of these marks is to show that the metal of the item upon which they are stamped is of a certain level of purity. The metal is tested and marked at special offices, regulated by the government, known as assay offices. Only metal of the required standard will be marked. It is a form of consumer protection, whose origin goes back almost 1000 years.