Prince William's royal coat of arms was revealed Sunday and included a unique addition — a tribute to his late mother, Princess Diana.
The coat of arms, which marks the prince's 18th birthday, incorporates aspects of the royal arms used by Queen Elizabeth II and Prince Charles in addition to a small red escallop shell derived from the Spencer coat of arms.
The escallop motif, used by Princess Diana, has been borne by the Earls Spencer since the 16th century and was a popular symbol for medieval pilgrims.
The design was incorporated at Prince William's insistence, a palace spokeswoman confirmed. The design was also approved by the queen and Prince Charles.