The monarch also wasn't in attendance for Prince Louis' royal christening last year

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Queen Elizabeth and Prince Philip
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Meghan Markle and Prince Harry‘s son Archie was missing a very important guest at his royal christening: great-grandmother Queen Elizabeth.

The monarch and her husband Prince Philip, who are believed to be at Sandringham together, were noticeably missing from the ceremony on Saturday, but it wasn’t a break in royal tradition. Although the Queen attended the christenings of great-grandkids Prince George and Princess Charlotte, she did not attend Prince Louis’ christening last year.

The decision that she would not be attending Louis’ event was “mutually agreed” between the Queen, Prince William and Kate Middleton “some time ago,” a palace source told PEOPLE at the time.

The Queen’s absence is likely due to her busy schedule. She just capped off a heavy work week and she has another one in the week ahead. And at 93, she has been handing over certain roles and patronages to senior members of the royal family.

Philip, who turned 98 last month, is retired from public duty and doesn’t attend as many events.

Credit: CHRIS ALLERTON/AFP/Getty Images
Credit: CHRIS ALLERTON/AFP/Getty Images

The Queen is also preparing for her summer holiday at Balmoral Castle in Scotland. She typically heads north to her Scottish residence in late July each year as Buckingham Palace prepares to open its doors to visitors. But it’s not all play for the monarch while she’s away in the Scottish Highlands. She does continue to work, reading her diplomatic papers in the famous “red boxes” that are delivered daily. She will also continue to hold audiences and undertake some public engagements.

During her summer holiday, she will also entertain many of her immediate family members. Harry took Meghan to his grandmother’s Scottish highlands estate before their engagement was announced.

Palace sources say there is no cause for any concern about the health of either her or Philip, who turned 98 last month. Philip has appeared at several royal weddings over the past year and has been spotted driving around Windsor Estate after getting into a car crash earlier this year.

Those attending the royal christening include Prince William, Kate Middleton, Prince Charles and Camilla, Duchess of Cornwall and Meghan’s mother Doria Ragland.