James Alexander Philip Theo Mountbatten-Windsor is the second child of the Earl of Wessex and Sophie, Countess of Wessex. He was born on 17 December 2007 and is twelfth in line to the throne.
He does not have the style HRH. Viscount Severn is a subsidiary title of his father the Earl of Wessex and is therefore used as a courtesy title. It may be assumed that he will succeed to the title Earl of Wessex as and when his father becomes Duke of Edinburgh.
Viscount Severn was christened on 19 April 2008. He became the first royal baby to wear a hand-made christening gown commissioned by The Queen, replacing the gown made for one of Queen Victoria’s daughters, which has now been preserved. In 2018 he acted as a special attendant at the weddings of his cousins Prince Harry and Princess Eugenie, alongside his sister Louise.