William and Kate appeared for the first time with their three children at Prince Louis' christening.
Though royal christening's usually occur in Buckingham Palace, the chapel has a special place in the monarchy, having housed several important occasions.
The prince's six godparents were among the guests including the Duke's close friend Guy Pelly, who was once dubbed William and Harry's "court jester" for his wild ways.
Louis, the third child of the Duke and Duchess of Cambridge, will be christened in a private ceremony at St. James's Palace Monday afternoon.More news: McConnell calls Kavanaugh a ‘superb’ court pick
The young prince, who has an older brother George, 4, and sister Charlotte, 3, was baptised using water from the River Jordan.
Prince Louis was carried into the chapel by his beaming mother, wearing the handmade replica of the Royal Christening Robe, which in 2008 replaced the original which had been worn for all royal christenings since that of Queen Victoria's eldest daughter in 1841.
"She loved all the old classics and Harry had the brilliant idea of starting a little library of first editions for Louis, Charlotte and George to enjoy as they get older".
With both fabrics sourced from United Kingdom locations, and a local seamstress chosen to craft the piece, Queen Victoria supported local industries through her fashion choice.
The royal family stepped out in force for the royal christening.More news: Protesters confront McConnell outside Kentucky restaurant
He is one of Queen Elizabeth's seven great-grandchildren.
St James's Palace was built between 1531 to 1536 by King Henry VII and dedicated to Saint James the Less.
Prince Louis was born on April 23, 2018, and on July 9, he was christened for the world to see.
He was welcomed into the Christian faith dressed in the same frilly, cream gown used for George and Charlotte.More news: Raikkonen just "messed up" in Hamilton clash, says Rosberg
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