Aristotle, Plato and Socrates all believed that swans singing prowess was heightened as death approaches, giving rise to the idea of the swan song, or the final performance.

During the Middle Ages, the mute swan was considered to be a valuable commodity and was regularly traded between noblemen. The owners of swans were duty bound to mark their property by way of a succession of unique nicks in the beaks of their birds. It was the duty of the Royal Swanmaster to organise the annual swan-upping, a tradition that survives to this day.

The role of swan-upping was to round up unmarked cygnets and once the parentage of the cygnets had been established to the Swanmaster's satisfaction, the birds could be marked appropriately and returned to the wild. The ceremony exists these days in a largely symbolic form, although as an exercise it is useful in monitoring the condition and number of swans on the Thames.

The only two companies that still observe the tradition of owning swans on the Thames are the Worshipful Companies of Vintners and Dyers. The Royal swans are no longer marked, but an unmarked mute swan on the Thames is regarded as belonging to the Queen by default. The Queen still maintains an officially-appointed Swan Keeper, and the ceremony still takes place on the Monday of the third week in July.

The Queen has a prerogative over all swans in England and Wales. The Swan Keeper also despatches swans all over the world, sent as gifts in the Queens name.