After the christening, William and Kate are hosting a private tea at Clarence House.
Queen Victoria holding her son, Prince Edward Albert of York, in 1984. But the two were not at the ceremony.
After retiring from public life last September, Prince Philip, 97, has appeared on only a handful of occasions.
As usual, the christening was an intimate affair.
Harry's hope is to establish a library for Louis, who was born on April 23, in tribute to the baby's late grandmother, Princess Diana, The Sun claims. Prince William wore a sharp blue suit and was hand-in-hand with George and Charlotte who wore a white short set and blue and white printed dress respectively.
Who are Prince Louis' godparents? They included old school friends and a Middleton cousin.
The godparents are all friends or family of William and Kate. As after George and Charlotte's baptisms, guests will be served slices of the duke and duchess's wedding cake.
"They are rewarding the loyalty of their really close friends and keeping the godparents from the tight, inner circle", one source said, commenting on the fact that some of Prince Louis' godparents have direct ties to some other royal godparents. The christening photo will be released in coming days, the palace said. One day you're shaking hands with the Archbishop of Canterbury at Prince Louis's christening, the next you're staring up at the sky to watch a military flyover at Buckingham Palace.
While attending Prince Louis' christening, big sister Princess Charlotte gave photographers a sassy message and a stare-down. "Please join me in praying for him and his family on this special day".
Once the brief ceremony concluded, the royal family made for the exits - with Princess Charlotte offering a parting wave to the cameras.
Britain's Prince Charles, Prince of Wales (R) and Britain's Camilla, Duchess of Cornwall arrive for the christening.
According to tradition, water from the River Jordan was used at the christening.