Norway’s royal family has been thrust into an extraordinary legal reckoning after Crown Prince Haakon’s stepson, Marius Borg Høiby, was convicted of rape and domestic violence and sentenced to four years in prison following a seven-week trial.

Oslo District Court found the 29-year-old guilty on two rape counts, including one assault in the basement of the crown prince’s home. Høiby became part of the royal household when his mother, Mette-Marit, married Haakon in 2001.

He was cleared of two additional rape allegations.

In total, the court convicted Høiby of 34 out of 40 charges. Alongside the rape convictions, the verdict included findings of domestic violence against a then-girlfriend, as well as drug possession and supply.

During proceedings, judges heard extensive evidence about Høiby’s drug addiction, self-recorded videos of sexual encounters, and hundreds of electronic messages exchanged with former partners that prosecutors said supported the case.

Prosecutors had asked for a sentence of seven years and seven months. They argued that the four women who accused him of rape — both in the counts that were upheld and those he was acquitted of — had been too unconscious or too incapacitated to resist after attending parties.

“The court finds it is proven she was not able to resist the action,” judge Jon Sverdrup Efjestad said of the rape at the crown prince’s home, as he delivered the unanimous decision of the three-judge panel.

Høiby denied the most serious allegations but acknowledged several lesser offences, including transporting 3.5kg of marijuana, breaching restraining orders and committing traffic violations.

His lawyer, Petar Sekulic, said Høiby would appeal the judgment, speaking to the newspapers VG and Aftenposten.

The prosecution said it would weigh its own appeal after reviewing the full 127-page ruling.

“This is a victory for our justice system,” prosecutor Sturla Henriksbø said.

Marius Borg Høiby pictured alongside his mother Mette-Merit

“No one can get away with serious criminal acts based on who they are or who they are related to.”

The royal household, which has previously expressed sympathy for everyone affected by the case, declined to offer a reaction to the verdict.

“The matter has been considered by the courts, and we have no comment on the outcome,” a spokesperson said.

No other royal family members attended the trial.

The court found that Høiby subjected a then-girlfriend to domestic violence from mid-2022 through autumn 2023. Testimony described repeated assaults, including punches to her face, choking, slamming a door into her face and throwing objects at her.

For medical reasons, Høiby followed the verdict via video link from prison.

He has repeatedly been refused permission to visit his mother, who is suffering with pulmonary fibrosis and needs a lung transplant.

Only one of the women who accused him of rape was present in court for the verdict.

She cried after the judge upheld her case.

Although Høiby holds no royal title and carries no official duties, the case has gripped Norway because of his connection to the heir to the throne.

Norway’s monarchy, like other understated Scandinavian royal families, has long cultivated an image of everyday normality — sending children to state schools and sharing public pastimes such as skiing and surfing.

But the trial has damaged that standing, coming as it did alongside Crown Princess Mette-Marit’s apology for contacts with late US sex offender Jeffrey Epstein.

A Norstat survey taken in February during the trial found support for retaining the monarchy fell to a record low of 60%, before rebounding to 64% in May.

John Christian Elden, a lawyer representing one of the victims, said the four-year sentence aligned with updated rules that draw a clearer line between rape involving intercourse and rape without it.

The two rape counts for which Høiby was convicted did not involve intercourse.

Mr Henriksbø said the court had also factored in newer practice that weighs whether consensual sex occurred immediately before the rapes — which, he said, had happened in this case.