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Queen Elizabeth II spent the night in a hospital Wednesday and was released Thursday, Buckingham Palace confirmed.

“Following medical advice to rest for a few days, The Queen attended hospital on Wednesday afternoon for some preliminary investigations, returning to Windsor Castle at lunchtime today, and remains in good spirits,” a palace spokesman said in a statement (via CNN).

The 95-year-old Queen was scheduled to make an appearance at a church service in Armagh, Northern Ireland, for the first time since 2016, but canceled on the advice of her doctors. A palace insider told The New York Times that the Queen she “reluctantly accepted medical advice to rest for the next few days.”

She will reportedly reschedule the visit.

According to The Sun, there was concern that the monarch would be exhausted after a number of consecutive public events (a total of 10 engagements over the course of 19 days), including hosting Bill Gates at Windsor Castle on Tuesday evening.

Royal historian Penny Junor told The New York Times, “To have engagements day after day after day, where you’ve got to remember people’s names and think of something to say, that takes a lot of energy. It’s like going to a wedding every day.”

A palace source told CNN that the Queen resumed “light” duties, with The Sun reporting that she’d resumed her “red box” duties of reading over mail and important documents.

Sources also alleged that the overnight stay may have just been a practical matter more than a medical emergency, as the hospital was 26 miles from Windsor Castle and it was late at night.

British Prime Minister Boris Johnson sent get well thoughts the Queen’s way.

“I think everybody sends Her Majesty our very, very best wishes, and certainly we have from the government,” he said during a public appearance. “I’m given to understand that actually Her Majesty is characteristically back at her desk at Windsor as we speak. But we send her every possible good wish.”

Queen Elizabeth was last hospitalized overnight in 2013 for a gastrointestinal illness. She has been hospitalized a total of five times within the last 40 years.

Leading to her hospitalization this week, the Queen was seen walking with a cane for the first time since she was recovering from knee surgeries in 2003 and 2004.

The Queen’s next scheduled public appearance is for the United Nations’ COP26 climate summit in Glasgow, Scotland, on Nov. 1, 2021.

Whatever her health condition, don’t blame anything on her age: Queen Elizabeth issued a cheeky response when nominated for “Oldie of the Year,” noting that she “does not believe she fits the relevant criteria.”

Next, find out what Prince William had to say about the upcoming climate summit.