When swans were first introduced into Britain (probably from Cyprus about the thirteenth century) they were very rare and were considered a great delicacy in the kitchens of the nobility. They were proclaimed royal birds, and the reigning sovereign was, and still is, Seigneur of the Swans. Ownership of all the swans on the Thames is divided between the Queen and two of the oldest trade Companies in the City of London, the Dyers and the Vintners. These two Companies were granted the privilege in the reign of Elizabeth I. Once a year, usually in the second half of July, the ceremony of Swan-Upping and Marking is performed from gaily flagged skiffs by the Queen's Swanmaster and the Swanmasters of the Dyers and Vintners. The Swanmasters wear special gold-braided uniforms, and their assistants are dressed in striped jerseys. Their task is to mark cygnets on the Thames from London Bridge to Henley-on-Thames.Royal swans are not marked, but those of the Dyers' Company are recorded by one nick in the bill; those of the Vintners by two nicks. There are always several hundred birds to be marked, and the job takes a week or more to complete.