King Charles III turned 74 on Monday, with ceremonial gun salutes booming across the British capital to mark his first birthday as monarch.
The former prince of Wales has thrown himself into his new role following the death of his mother, Queen Elizabeth II, on September 8.
His birthday fell a day after Remembrance Sunday, when he led a sombre tribute to Britain's war dead at London's Cenotaph for the first time as monarch.
Liveried troops fired salutes in London parks and from the Tower of London on the banks of the River Thames.
A military band played "Happy Birthday" at the daily Changing of the Guard ceremony outside Buckingham Palace.
Charles has not scheduled any public appearances for his birthday.
But he was pictured in a new photograph wearing a tweed jacket and corduroy trousers posing by an ancient oak tree to mark his appointment as Ranger of Windsor Great Park, west of London.
The post was previously held by his father, Prince Philip, who died in 2021.
In May next year, Charles, who was born on November 14, 1948, will become the oldest British monarch ever crowned.
He became heir to the throne aged just three and spent most of his life waiting to succeed his mother.
Since doing so in September he has immersed himself in his new role, although has held true to his word that he would not "meddle" in politics as king.
Despite being an outspoken advocate of environmental causes, he has not gone the United Nations COP27 summit on climate change, following government advice.
He has met a string of foreign dignitaries, including ambassadors and heads of state, as well as making public appearances around the country.
Last week, he hosted Nigerian President Muhammadu Buhari and Jordan's King Abdullah II, met refugees from Ukraine and Afghanistan, and visited Northern Ireland.
- Dodging eggs -
Queen Elizabeth II saw 15 British prime ministers come and go during her record-breaking 70-year reign.
Charles has already had two -- Liz Truss, whose short-lived tenure ended in a furore over her tax plans, and Rishi Sunak, who was defeated by Truss during a party leadership contest but ended up replacing her.
When he met Truss, who accompanied Charles on a tour of the nation after his mother's death, the monarch was picked up saying: "Back again. Dear oh dear."
Last week, he had to dodge eggs thrown by a student opponent of the monarchy during a walkabout in York, northern England.
Yet his first months have been relatively well received.
An Ipsos poll in late October found Charles's approval rating had risen 11 percent since March, to 54 percent, behind his eldest son, William, daughter-in-law Catherine, and his only sister Anne.
Right-wing tabloid The Sun headlined a story for his birthday: "Bonnie King Charles".
"Two months have gone extremely well," royal commentator Richard Fitzwilliams told AFP, praising Charles's energy and "the way he handled events after his mother's death, which I thought was excellent".
At a time of political turmoil, the royals provide a "symbol of national unity, which the politicians frankly have not provided", Fitzwilliams added.
Obstacles loom ahead though, most notably the contents of the confessional memoir "Spare", penned by Charles's estranged younger son Prince Harry, which is set to come out in January 2023.
The royal-themed drama "The Crown" this month released its fifth series, covering the most scandalous years of the breakdown of Charles's marriage to his first wife, Diana.
The fictionalised Netflix drama rehashes the circumstances behind Diana's bombshell 1995 BBC interview, in which she lifted the lid on Charles's adulterous relationship with Camilla Parker Bowles.
In the interview, Diana also admitted to being unfaithful and expressed doubts about Charles's fitness to be king.
"The Crown" also covers the tabloid newspaper publication of the transcript of an intimate phone call between Charles and Camilla, which also dented his reputation at the time.