This livery collar, or chain of office has been used in both The Tudors and The Hollow Crown. Livery collars were generally used to denote the holding of an office, or as a symbol of fealty to a specific person or house. This specific design, usually referred to as a “Collar of Esses” was used as early as 1371. There is speculation that the "S" stands for "Soverayne" (sovereign) or Spiritus Sanctus (Holy Spirit), though the actual meaning is unknown.
Thoughout the reigns of Henry IV, V and VI, the “Esses” were typically considered to be a badge of the House of Lancaster. The pendant that adorned the end of the chain at this time was generally a white swan. The chain was used again during the reign of Henry VIII, where Hans Holbein’s famous portrait of the Lord Chamberlain, Sir Thomas More was painted wearing a chain of Esses adorned at the end with a Tudor Rose.
This particular chain, which was used first for the Tudors had to remove the Tudor Rose for its usage in The Hollow Crown, as the Wars of the Roses had not yet ended, and the Tudor Rose – the combination of the Houses of York and Lancaster did not yet exist.