When Prince William and Kate Middleton were choosing a date for this important event, it's likely their main reason for picking July 9 was that it fit the busy schedules of those involved, but it actually has a very sweet royal significance, too.
It's also where the coffin of Diana, Princess of Wales laid for a week before her burial.
Mrs Robert Carter, the couple's close friend; she went to school with Kate and her sister-in-law, Sophie, is godparent to Princess Charlotte.
The six will attend Prince Louis' christening on Monday, taking part in what is expected to be a traditional ceremony at the Chapel Royal in St James's Palace. The Archbishop of Canterbury, Justin Welby, will conduct the royal baby's baptism.
On May 19, before she had even confirmed she was expecting, Pippa seemed to be glowing at Meghan Markle and Prince Harry's wedding in a mint green and patterned silk dress. Just like his siblings Prince George and Princess Charlotte, the young prince will be baptized into the Church of England, the state church of England, of which the queen is Supreme Governor.
Who will christen Prince Louis?
Power Ranking The Four World Cup Semi-Finalists
That said, let's talk about why England will be lifting the World Cup trophy on July 15 in Moscow. At this stage of the tournament, there are only four days between matches.
The baby prince - Louis Arthur Charles - was born in the private Lindo Wing of St Mary's Hospital in Paddington, London, on April 23 - St George's Day - weighing 8lb 7oz.
It will be the first time the Duke and Duchess of Cambridge and their three children have been seen together.
Prince Louis will wear the handmade replica of the Royal Christening Robe, made by The Queen's dressmaker, Angela Kelly.
Following the special service, the Cambridges will pose for the first official family photos.
The godparents of the newest royal prince have been announced ahead of his Christening today.
Five are close friends, while one is a family member.