CHICHESTER, ENGLAND – NOVEMBER 30: Queen Elizabeth II is seen at the Chichester Theatre while visiting West Sussex on November 30, 2017 in Chichester, United Kingdom. (Photo by Stuart C. Wilson/Getty Images)

Queen Elizabeth II died at the age of 96. The longest-reigning monarch in Britain’s history and just celebrated 70 years on the throne with her Platinum Jubilee earlier this summer.

“The Queen died peacefully at Balmoral this afternoon,” Buckingham Palace announced in an official statement on Thursday. “The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow.”

Earlier in the day on Thursday, Buckingham Palace announced in a statement that the Queen was placed under medical supervision. “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 statement said. They added that the Queen “remains comfortable and at Balmoral.”

It came a day after the Queen welcomed the new Conservative Party leader Liz Truss, who will replace Boris Johnson as Prime Minister, to Scotland, where they were photographed together.

Queen Elizabeth, who presides over the United Kingdom and of 14 other sovereign countries, became queen at 25 years old in 1952 after the death of her father, King George VI. (Her father became king after his brother, King Edward VIII, abdicated the throne.) She celebrated her coronation on June 2, 1953. In 2015, she became the longest-serving British monarch surpassing her great-great grandmother Queen Victoria.

On November 20, 1947, she married Philip Mountbatten, a former prince of Greece and Denmark and commander in the British Army, at Westminster Abbey. The coupe had four children together, Charles, Prince of Wales; Anne, Princess Royal; Prince Andrew, Duke of York; and Prince Edward, Earl of Wessex.

Prince Charles will assume the throne immediately, though the coronation ceremony will typically happen a year later, according to PEOPLE.

The Queen is the second-longest reigning monarch in history, following French King Louis XIV who reigned for 72 years. 

Over her reign, she remarkably never fell victim to the pitfalls that wealth and privilege can bring. She was fiercely dedicated to protecting the institution — something she undoubtedly learned after Edward VIII abdicated the throne, leaving her father George VI next in line. She exemplified quintessentially British values, like the famous British reserve and unique sense of humor, which has been a constant in her people’s lives throughout her seven-decade reign.