The eldest son of Norwegian Crown Princess Mette-Marit was on trial in Oslo on Tuesday facing a string of charges including rape, domestic violence, property damage, drug offenses and traffic violations.

Among the most serious charges are allegations that Marius Borg Hoiby, 29, raped and sexually abused several women between 2018 and 2024, allegedly filming himself committing some of the acts while the victims were asleep.

Prosecutors have said he could face up to 16 years in prison if convicted at the trial, which is scheduled to last until March 19 and expected to garner considerable media attention.

Hoiby has admitted some of the more minor offenses and has previously claimed he has suffered from "mental troubles" and struggled "for a long time with substance abuse."

But when proceedings opened on Tuesday morning, he pleaded not guilty to the four rape charges.

Prosecutor Sturla Henriksbo told the AFP news agency that Hoiby would "neither be treated more leniently nor more severely because of his family."

Norway: Royal scandal involving arrests and Epstein

Hoiby, who is the stepson of the heir to the Norwegian throne, Crown Prince Haakon, was repeatedly arrested in 2024 for various alleged misdemeanors. He was indicted in August 2025 but was free pending trial until Sunday, when he was arrested again.

The new allegations of assault, threats with a knife and violation of a restraining order are not the subject of Tuesday's trial, but a judge in Oslo on Monday granted the prosecutors' request to keep him in detention for up to four weeks on the grounds of a risk of reoffending.

The Norwegian royal family, headed by the 88-year-old King Harald V, is generally popular in Norway, but the Hoiby trial comes at a particularly inopportune time.

As the son of Crown Princess Mette-Marit from a previous relationship, Hoiby himself does not hold any royal titles or official positions. But his mother is currently back in the news after being named several hundred times in the latest batch of the Epstein files which were released on Friday.

Mette-Marit admitted back in 2019 to having had contact with the late convicted sex offender Jeffrey Epstein, telling Norwegian media: "I showed poor judgment and regret having had any contact with Epstein at all. It is simply embarrassing."

Edited by: Elizabeth Schumacher