The trial of Marius Borg Høiby, son of Norway's crown princess, has heard the first account from a woman he is alleged to have raped at a party in 2018.

The woman told the court in tears she had no recollection of what had happened, after an earlier sexual encounter that lasted a matter of seconds.

Facing 38 charges against him, Marius Borg Høiby pleaded not guilty to raping four women and other serious offences but admitted breaking a restraining order, transporting marijuana and speeding while "partly" admitting threats and aggravated assault.

He is due to take the stand for the first time in the trial on Wednesday afternoon.

Although he has grown up as Crown Prince Haakon's stepson, Marius Borg Høiby is not a member of the royal family or a public figure.

However, the first count of rape is alleged to have taken place in his parents' basement on their Skaugum estate outside Oslo.

As the trial began at Oslo district court on Tuesday, the palace came under increasing pressure to explain his mother's three-year exchange of messages with the late sex-offender Jeffrey Epstein between 2011 and 2014.

Crown Princess Mette-Marit has already admitted to "poor judgement", after details emerged of a four-day stay at his home in Palm Beach, Miami. But the palace has said little more as further revelations have emerged.

No photos were allowed as her son entered courtroom 250 at Oslo district court at the start of a seven-week trial.

Wearing thick-rimmed glasses, a brown sweater and olive-green trousers, the blond defendant fiddled with a bracelet, speaking very quietly as he pleaded not guilty to raping four women. He later removed his sweater and sat in a plain, white T-shirt.

Prosecutor Sturla Henriksbø said he would be treated no differently than any other Norwegian. But in an impassioned opening statement, defence counsel Ellen Holager Andenæs said he had already been subjected to prejudicial treatment from the media.

It would be strange, she said, if someone facing such a "tsunami of negative publicity over such a long time" did not feel they were losing control of their life and destiny.

Heavy court restrictions have been imposed on the trial, with a ban on photos of the defendant or the women he is alleged to have raped inside or outside court.

While much of the first day was open to reporters, the doors were closed for the trial to hear from the first woman to give evidence in the case.

A small number of journalists were allowed to follow proceedings in an adjoining room, and details of the young woman's evidence have emerged from their accounts.

Describing the situation as surreal and overwhelming, she said it was unfair she was being dragged into the criminal case and it was the last thing she wanted. The alleged events took place in 2018 and it was not until after the defendant's arrest in 2024 that police found videos on his phone.

She told the court that they had consensual sex for a few seconds before she put an end to it. Then she said there was a "big black hole" in her memory. Asked if she had fallen asleep afterwards, she was adamant that she had not.

Her testimony is due to continue on Wednesday. All four of the women were incapacitated at the time of the alleged rapes. The alleged incidents took place after consensual sex.

Marius Borg Høiby's defence counsel told the court that he had pleaded not guilty to rape because he saw all the incidents as "completely normal and voluntary sexual relations".

She said the court would need to decide whether the four women had been unable to prevent what had happened, and if he should have understood that they were asleep or unable to resist.

The defendant will return to court on Wednesday. He will spend the first four weeks of the trial in custody, as he was arrested two days before it began on suspicion of assault, making threats with a knife and violating a restraining order.

The case will be decided by three judges - if they find him guilty, he could go to jail for at least 10 years.

The trial comes at an intensely difficult time for the royal family because of the continuing scandal surrounding the crown princess's correspondence with Jeffrey Epstein.

Norway's royal family remains very popular, with a Norstat opinion poll not long ago suggesting 73% were in favour of it.

But there are signs of disquiet among Norwegians from snap polls this week.

One survey by the Verdens Gang website suggested that its popularity was down to 60.9%. The same poll also suggested 44% of Norwegians believed Mette-Marit should not become queen.

The palace sees opinion polls as snapshots that change over time, and it will have been comforted by a vote by Norwegian MPs as the trial got under way.

Traditionally, they vote once in every parliament on a republican motion to abolish the monarchy and the motion came up by coincidence on Tuesday. The result was never in doubt - and only 26 of the 169 members of the Storting supported abolition.