Prince William and his wife Kate's third child, 11-week-old Prince Louis was christened during a private ceremony Monday.
The little prince was sleeping in his mother's arms when the family arrived at The Chapel Royal at St. James' Palace in London.
The duchess was heard by BBC reporters describing her son as "relaxed and peaceful."
The Archbishop of Canterbury, the Most Reverend Justin Welby, baptized the baby.
The young prince wore the same lace and satin christening gown that his siblings Charlotte and George wore at their baptisms.
The Duke and Duchess of Cambridge chose the hymns "O Jesus, I Have Promised" and "Lord of All Hopefulness" for the short ceremony.
Newlyweds Prince Harry and Duchess Meghan attended the ceremony. However, Queen Elizabeth II and her husband Prince Philip did not attend.
The queen was traveling back from Norfolk Monday and had a busy week of preparations before President Donald Trump's visit to Windsor Castle on Friday.