In 1965, a Norwegian woman gave birth to a girl in a private hospital. Seven days later she returned home with a baby.
When the child developed dark curls that made her look different from herself, Karen Rafteseth Dokken assumed she took after her husband's mother.
Nearly six decades later, the true reason was discovered. Her biological daughter had been mistakenly switched at birth in the maternity ward of the hospital in central Norway.
Mona, the girl raised by the woman, was not the baby she gave birth to.
The babies - one born on 14 February and the other on 15 February 1965 - are now 59-year-old women who, along with Mrs Rafteseth Dokken, are suing the state and the municipality.
In their case, at Oslo District Court, they said their human rights were violated after authorities discovered the error - when the girls were teenagers - and covered it up.
They said that officials had undermined their right to a family life, a principle enshrined in the European Convention on Human Rights, and have demanded an apology and compensation.
Mrs Rafteseth Dokken, now 78, was in tears as she described learning so many years later that she was given the wrong baby.
"It was never my thought that Mona was not my daughter," she told the court. "She was named Mona after my mother."
Mona described a sense of never belonging as she grew up. The uncertainty pushed her in 2021 to have a DNA test, which showed that she was not the biological daughter of those who raised her.
But the woman who raised the other baby knew long before.
A routine blood test in 1981 showed that the girl in her care, Linda Karin Risvik Gotaas, was not biologically related.
The woman raising her, however, did not pursue a maternity case. Norwegian health authorities were informed of the mix-up in 1985, but did not tell the others involved.
Rights 'violated' by state - lawyer
Both women who were swapped at birth have said in interviews that it was a shock to learn about the mix-up.
However, they said the knowledge made pieces of their lives fall into place, explaining differences both in terms of appearance and demeanour.
Kristine Aarre Hanes, representing Mona, said the state "violated her right to her own identity for all these years. They kept it secret".
She could have learned the truth when she was a young adult, but instead "she did not find out the truth until she was 57".
"Her biological father has died. She has no contact with her biological mother," Ms Aarre Haanes added.
Circumstances surrounding the 1965 swap at Eggesbones hospital are unclear, but media reports suggest there were several cases during the 1950s and 1960s where children were accidentally swapped at the same institution.
At the time, babies were kept together while their mothers rested in separate rooms.
In other cases the errors were spotted before the children were permanently placed with the wrong families, according to the reports.
No plans for public inquiry - official
An official from the Norwegian ministry of heath and care services said the state was unaware of similar cases and that there were no plans for a public inquiry.
Asgeir Nygaard, representing the Norwegian state, is contesting the action on the grounds that the 1965 switch took place in a private institution and that the health directorate in the 1980s did not have the legal authority to inform the other families when it discovered the error.
"Documentation from that time indicates that government officials found the assessments difficult, inter alia because it was legally unclear what they could do," Mr Nygaard said in a statement.ahead of the opening of the case.
"Therefore, in court, we will argue that there is no basis for compensation and that the claims being made are in any case statute-barred."
The hearing will continue until Thursday, but it is not clear when a ruling is expected.
