Britain's Queen Elizabeth II turned 95 on Wednesday, less than a week after the funeral for her husband, raising questions about how long her reign will continue.
The combination of Prince Philip's funeral and her birthday highlights that her reign – already the country's longest at 68 years – is finite but certainly not over.
Since 2013, the queen has passed more responsibilities to Prince Charles and as she closes in on her centenary, others such as Prince William and Kate, the Duke and the Duchess of Cambridge, could take on additional duties.
"The queen is certainly moving now into the twilight of her reign and a new phase of her reign," said Anna Whitelock, director of the Centre for the Study of Modern Monarchy at the University of London.
"She now is a widow and it remains to be seen how she’s going to respond to that."
She is marking her birthday in low-key fashion at Windsor Castle with some family members expected to join her.
In a letter written on Windsor Castle notepaper she acknowledged the "support and kindness" shown to her from around the world.
"I have, on the occasion of my 95th birthday today, received many messages of good wishes, which I very much appreciate.
"While as a family we are in a period of great sadness, it has been a comfort to us all to see and to hear the tributes paid to my husband, from those within the United Kingdom, the Commonwealth and around the world.
"My family and I would like to thank you all for the support and kindness shown to us in recent days."
UAE President Sheikh Khalifa, Sheikh Mohammed bin Rashid, Vice President and Ruler of Dubai, and Sheikh Mohamed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces, all sent birthday messages congratulating the queen.
British Prime Minister Boris Johnson was also one of many people to send best wishes to the monarch.
"I have always had the highest admiration for Her Majesty and her service to this country and the Commonwealth," Johnson said on Twitter. "I am proud to serve as her prime minister."
Royal supporters saw Philip's death as a symbol of national unity but the BBC received more than 100,000 complaints about its decision to drop scheduled programmes – across TV, radio and online – for coverage of Prince Philip’s funeral.
By the time he queen was crowned on June 12, 1953, after the death of King George VI, Philip had been her husband for five years.
She has seen 14 British prime ministers take power, was the first British royal woman to serve full-time in the military and is credited with the creation of the dorgi, a corgi dachshund crossbreed.
Without the man she called her "strength and stay", she will continue, but there will be changes – a point illustrated at the funeral when she sat alone during the service.
"Symbolically, the transition towards the succession is already under way," historian Ed Owens said.
"I anticipate that we're going to see a lot more of Prince Charles in the next couple of years so that we, as a people, start to see him in his future role as king."
Questions about the end of the queen’s reign will also fuel debate over the long-term future of the British monarchy.
