Prince Harry accompanied by his wife Meghan Markle was of course the part for the ceremony is highly symbolic of his nephew, to whom he has offered the gift terribly generous, while the absence of the Queen Elizabeth II announced in the morning made noticed.
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.
Instead, Prince William and Kate Middleton have appointed friends and other relatives to look after their third child.
As Kate chatted to the archbishop while holding Louis, she could be heard describing her sleeping son as "very relaxed and peaceful".
"I'm delighted and privileged to be christening Prince Louis today - a precious child made in God's image, just as we all are", Archbishop Justin Welby said on Twitter before the ceremony.
Kensington Palace said the Queen's no-show was not due to illness and had been mutually agreed with the Duke and Duchess of Cambridge some time ago.
Getty Images | Chris Jackson
The Cambridges arrived with Prince Louis in Middleton's arms.
Louis was born on April 24 - St. George's Day, England's national day - at St Mary's hospital in central London weighing eight pounds and seven ounces (3.8 kilogrammes). The three godmothers are Hannah Gillingham-one of Kate's school friends-cousin Lucy Middleton and Laura Meade, wife of Prince William's friend James Meade, who is Princess Charlotte's godfather.
Guests who attended the christening were served tea and fruit cake, which was originally baked for and served at the Duke and Duchess of Cambridge's wedding in 2011.
The christening was not the first time the princess has unleashed her sass.
At the end of the service the duchess fanned herself with the order of service against the stifling heat as she walked from the chapel.
Princess Charlotte had a sassy message for photographers as she left her brother's christening on Monday: "You're not coming".More news: Engand's Dele Alli busts out Fortnite dance in World Cup match