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 that had been worn for all royal christenings since that of Queen Victoria's eldest daughter in 1841.
Accompanied by her husband, Meghan stunned in a green hat and dress, and according to the team at Meghan's Mirror, wore since-sold out heels by Manolo Blahnik. She also wore her hair in a low chignon, topped with a white, flowered headpiece.
While William was also dressed in full RAF uniform, his ensemble differed slightly to Harry's by wearing a blue sash across his body.
However neither Prince Harry nor Meghan were named among Louis' six godparents, with the honour going to Guy Pelly, who was once dubbed the "court jester", family friend Nicholas van Cutsem and William's school pal Harry Aubrey-Fletcher.
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Croatia have gone through two extra times and two penalty shootouts - they must be shot , physically and mentally. What I would like is the England from before, but now they are very strong and we have to respect them", he said.
Harry and Meghan will also head to Australia, Fiji, the Kingdom of Tonga and New Zealand in the fall for their first royal tour as a married couple.
Middleton's sister, Pippa Middleton, attended the ceremony, as did her brother James Middleton.
The Queen and Prince Philip were notably absent from the special occasion, however it has been confirmed that the 92-year-old monarch had previously agreed the arrangement with the Duke and Duchess due to work commitments, not health issues.