More than a decade ago, Andrew Mountbatten-Windsor's former wife, Sarah Ferguson, sent a birthday party invitation to Jeffrey Epstein.
The convicted US sex offender had been released from jail a few months earlier.
"Beatrice, Eugenie and I would love to invite you to celebrate the 50 years of Papa/Andrew," Ms Ferguson wrote.
Epstein did not attend. He was still under house arrest for procuring a girl younger than 18 for prostitution.
The St James Palace party went ahead without him.
Sixteen years later, the ex-prince awoke on the morning of his 66th birthday, stripped of his titles and ostracised by multiple family members, at Sandringham's Wood Farm.
The police were waiting for him.
Here's how the day unfolded.
Early morning arrest for disgraced former prince
It was 8am on Thursday, local time, when Thames Valley Police officers in unmarked vehicles descended on the Sandringham property.
The former prince has been staying at the Norfolk farmhouse since he was given notice of his eviction from Royal Lodge, his longtime residence on the grounds of Windsor Castle.
He officially relocated to the five-bedroom cottage on February 2.
King Charles's brother has faced intense scrutiny for years over his links to Epstein — particularly in the past few months with the release of the Epstein files.
The arrest, according to Thames Valley Police, was "on suspicion of misconduct in public office".
They did not provide further detail, but questions have been raised about whether the former prince shared sensitive information with Epstein while working as a UK trade envoy between 2001 and 2011.
Mr Mountbatten-Windsor has not publicly addressed the document-sharing allegations but has always strenuously denied any wrongdoing.
It is the first time a royal has been arrested in more than three centuries, according to journalist Emily Maitlis.
Ms Maitlis's now-infamous interview with the former prince, in which she grilled him over his links to Epstein, precipitated the catastrophic downfall of his reputation.
"The last time a royal was arrested was King Charles I in 1647," she told ABC Radio National Breakfast today.
"He was beheaded and that was briefly the end of the monarchy.
"So to say that this is a crisis moment, I think, doesn't begin to cover it."
Time critical for police as searches unfold
For police, the clock was now ticking.
In the UK, suspects can be held for 24 hours at most before they must either be charged or released pending further investigation.
They can apply to a judge for longer time if the suspected offence is serious.
The arrest meant police were able to "access computer equipment, files, photographs, any other evidence", according to former Metropolitan Police Chief Superintendent Dal Babu.
An arrest also gave police the right to take fingerprints, DNA and a custody photo.
Officers did not announce where Mr Mountbatten-Windsor was taken initially.
The police station he was ultimately released from in Aylsham is an hour's drive from Wood Farm, almost 60 kilometres away.
The station in north Norfolk is next to the Aylsham Police Investigation Centre.
According to advocacy organisation Rethink Mental Illness, a police investigation centre is a more "purpose-built" facility than a police station and is "used to hold and interview suspects, collect evidence and arrange court appearances".
It has not been made public which of the two facilities the former prince was held at.
Policing commentator Danny Shaw told BBC he would be placed in "a cell in a custody suite" with just a "bed and a toilet".
He would likely wait there until his police interview.
"[There will] be no special treatment for him," Mr Shaw said.
News goes global as police announce Andrew's arrest
By 10am, news had broken of the arrest.
Thames Valley police announced they had arrested a man — who they would not name — and were carrying out searches "at addresses in Berkshire and Norfolk".
Assistant Chief Constable Oliver Wright said: "Following a thorough assessment, we have now opened an investigation into this allegation of misconduct in public office.
"It is important that we protect the integrity and objectivity of our investigation as we work with our partners to investigate this alleged offence.
"We understand the significant public interest in this case and we will provide updates at the appropriate time."
It is unknown whether the former prince, sitting in custody, was aware of the media firestorm spreading around the globe.
Within minutes, the announcement has been splashed across the front pages and websites of every major news outlet in the world.
Business as usual for the king, despite brother's arrest
By midday, a search was under way at Andrew's former home in Windsor.
Uniformed police officers were seen along the fences of sprawling Royal Lodge in Windsor Great Park.
At the same time, photos of the police presence were going public, King Charles made his first and, so far, only statement on the arrest.
"I have learned with the deepest concern the news about Andrew Mountbatten-Windsor and suspicion of misconduct in public office," he said.
"What now follows is the full, fair and proper process by which this issue is investigated in the appropriate manner and by the appropriate authorities.
"In this, as I have said before, they have our full and wholehearted support and cooperation.
"Let me state clearly: the law must take its course. As this process continues, it would not be right for me to comment further on this matter.
"Meanwhile, my family and I will continue in our duty and service to you all."
Later, Queen Camilla personifies the "duty and service" commitment, arriving for an engagement at Westminster as planned.
She appeared cheerful as she greeted musicians at Sinfonia Smith Square Hall for a lunchtime orchestral performance.
Reporters were waiting for her as she climbed into a waiting car afterwards, asking: "Are you concerned about Andrew's arrest, your majesty?"
She waved, but did not answer.
Unanswered questions about Andrew's time in custody
At 6:50pm local time, a black Range Rover arrived at the police station.
Soon after 7pm, it left — with a photographer capturing a seemingly shell-shocked Mr Mountbatten-Windsor in the back seat.
Police have not released details of his time in custody.
It is unknown what he was asked or if he told police anything.
It is also not known if police found anything relevant to the investigation during searches of properties linked to the former royal.
Other police forces in the UK have said they are assessing potential inquiries into the Epstein files, however, none of these relate to the address of Mr Mountbatten-Windsor.
In a statement released almost 12 hours after his arrest, Thames Valley Police announced he had been released "under investigation".
"We can also confirm that our searches in Norfolk have now concluded," the statement said.
In the UK, being "released under investigation" means a person is suspected of committing a criminal offence, but the police do not have enough evidence to lay charges.
Mr Mountbatten-Windsor has not been charged with any offence.
