The longest-reigning monarch in British history, Queen Elizabeth II, passed away on Thursday at 96 years old, Buckingham Palace announced.
The queen's eldest son and former Prince of Wales, Charles, is now the king.
A statement on the official website of the royal family read, "The Queen died peacefully at Balmoral this afternoon. The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow."
The Union Jack flag outside Buckingham palace was lowered to half-staff in honor of Queen Elizabeth II.
On Thursday morning, a royal spokesman announced, "Following further evaluation this morning, The Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision. The Queen remains comfortable and at Balmoral."
The news outlet noted that an update about the queen's health was rare and suggested the situation was likely serious.
In response to the news, the family immediately rushed to be with the queen in her final moments.
ITV News Royal Editor Chris Ship posted on Twitter that all four of Queen Elizabeth II's children traveled to be by her bedside.
The queen was scheduled to virtually attend a Privy Council meeting on Wednesday but canceled the appearance due to doctors' recommendations.
On Tuesday, Queen Elizabeth II met with Boris Johnson and new Prime Minister Liz Truss at Balmoral Castle. Photographs from the meeting show the queen smiling as she meets with Truss in the drawing room. The queen appeared alert but frail, with significant bruising on her hand.
Before the meeting with Truss and Johnson, she had not been seen by the public for 47 days.
Truss learned about the queen's declining condition while delivering a statement in the House of Commons. Shortly after, the new prime minister posted on Twitter, "My thoughts - and the thoughts of people across our United Kingdom - are with Her Majesty The Queen and her family at this time."
The Highland Games took place last weekend, but Queen Elizabeth II could not attend the event for the first time during her 70-year reign. Royal sources told the Daily Mail that getting the queen to the games and having her sit in public for the duration of the event would have been problematic.
Public concern about the queen's health grew in response to the news that she would not attend the Highland Games, breaking a tradition started by Queen Victoria in 1848.