Prince Edward and his wife Sophie, the Countess of Wessex, christened their four-month-old baby on Saturday.
The child – whose official title is Viscount Severn – was christened James Alexander Philip Theo during a service at Windsor Castle’s private chapel.
The event – conducted by Right Reverend David Conner, the Dean of Windsor – was attended by close friends and family, including Edward’s parents Queen Elizabeth and Prince Philip, his brother Prince Andrew and his sister Princess Anne.
James is believed to have become the first royal to wear a replica of the family’s christening robe, specially commissioned in order to preserve the fragile original.
The old lace and satin gown, which was made in 1841, had been worn by all royal babies since the queen’s father George VI.
The baby’s godparents will be five close friends of Edward and Sophie – Denise Poulton, Jeanye Irwin, Alastair Bruce, Duncan Bullivant and Tom Hill.
James, who is eighth in line to the throne, was born by Caesarean section at Surrey’s Frimley Park Hospital on December 17.
Edward and Sophie also have a four-year-old daughter, Lady Louise Windsor.