Although Queen Elizabeth and Prince Philip were absent, Prince Harry and Duchess of Sussex Meghan Markle, Prince Charles and Duchess of Cornwall Camilla Parker Bowles, as well as Pippa Middleton and husband James Matthews, all attended their relative's christening.
Earlier, the royals and more than 2,200 people packed Westminster Abbey for a service also attended by Theresa May, defence secretary Gavin Williamson and Labour leader Jeremy Corbyn.
The Duchess of Cambridge could be seen wearing an Air Cadets Dacre brooch, the highest award any female cadet can achieve.
Jeff Spicer via Getty Images Queen Elizabeth II at the RAF centenary celebration.
Trump and the Russia Pipeline
" President Trump's brazen insults and denigration of one of America's most steadfast allies, Germany , is an embarrassment". Asked about Mr Trump's suggestion, NATO Secretary-General Jens Stoltenberg said he would focus on what has been agreed to.
At this point, it's safe to say that Kate Middleton has definitely noticed that Meghan Markle is giving her a good run for her money, at least when it comes to media attention.
Welcome (officially) to the world, little Prince Louis.
Nicholas Van Cutsem, Harry Aubrey-Fletcher, and Guy Pelly are Prince Louis' godfathers.
The youngsters stole the show, with Charlotte - who was dressed in a blue dress - sticking her tongue out and waving her arms around.
Per the official royal website, "Following the service, The Duke and Duchess of Cambridge will give a private tea at Clarence House".