Theresa Hiney Tinggal was 48 years old when she learned that she was adopted.

Tinggal immediately began searching for her biological family. For years, she wrote to newspapers and did interviews with the hope that if her birth mother were alive the two could be reunited. It was only last year, and with the help of DNA testing, that Tinggal located her birth family. By then, her mother had already died.

“Even now, it’s 16 years later and sometimes I think: ‘My God, did that really happen to me?'” Tinggal told Irish broadcaster RTE. “And the more I searched, the more I realized I wasn’t the only one.”

Tinggal was born to an unwed mother and then given up in a shadowy adoption. Her adoption was just one such case. Like Tinggal, many more people in the same situation have had the truth kept from them for decades.

Now, after years of adoption activists calling for action, the Irish government has finally apologized and is now attempting to shed light on one of the country’s biggest open secrets.

On Tuesday, Ireland’s Child and Family Agency, or Tusla, announced the identification of at least 126 cases of “incorrect registrations of birth” out of 13,500 records obtained from St. Patrick’s Guild, a Catholic adoption center long suspected of facilitating illegal adoptions. The births in question happened between 1946 and 1969, the agency’s statement said.

During a news conference, the country’s Minister of Children and Youth Affairs Katherine Zappone acknowledged that officials have known about these kinds of adoptions “for many years.”

“In effect, babies were given to a couple and registered as the child of that couple and not of the baby’s birth parents,” Zappone said. “However, it has been very difficult to prove because those responsible have covered it up.”

Zappone added that out of the identified cases, nearly 80 people “may be entirely unaware of the true circumstances of their birth because they never had contact with St. Patrick’s Guild.”

Following the public announcement, Prime Minister Leo Varadkar addressed Ireland’s parliament and condemned the adoptions, saying the disclosure of the cases would “open another dark chapter” in Irish history.

“I know some people will say that what’s in the past should be left in the past and perhaps we shouldn’t open this can of worms in many ways, but we’ve taken a different view as a government,” Varadkar said.

Varadkar also apologized.

“What was done was wrong, what was done robbed children, our fellow citizens, of their identity,” he said. “It was an historic wrong that we must face up to, and again on behalf of the government I’m very sorry for it.”

The revelations and the apology hark back to a period, not that long ago, when Ireland was still in the thrall of a Catholic church that had no tolerance and little compassion for unmarried mothers and their “out-of-wedlock” infants. Exposés in recent years have shed new light on decades of mistreatment of “fallen women,” who were sent to bleak homes run by various church orders. Thousands of women “deemed unfit for society,” were confined and forced to labor under the watchful eyes of nuns during their pregnancies. They were often forced to give their babies up for adoption.

And in some cases, the babies and children never made it out of the homes, dying premature deaths, their bodies buried in anonymous graves, most famously at a “mother and baby home” in the town of Tuam in County Galway, which was the subject of revelations and a government investigation that began in 2014.

The process of exposing the past and making amends began only after the church lost its powerful grip on the overwhelmingly Catholic nation, a decline of influence and respect most recently demonstrated by last week’s referendum vote to repeal Ireland’s constitutional ban on abortion.

Now, in an effort to address the falsified birth documents, Zappone announced that an independent review of a broad sample of adoption records would be done to see if “clear evidence of incorrect registrations” could be established.

The Child and Family Agency (Tusla) also said it will begin locating and contacting the 126 people affected, many who are in their 50s, 60s or 70s now. However, the agency noted that the process of tracing people is “often slow, labour-intensive work.”

“This is an extremely sensitive issue and one which we acknowledge may cause upset and anxiety for those affected, as well as adopted people, adoptive parents and birth parents across the country,” the statement said. “Tusla will ensure that those affected will be treated with dignity, respect, sensitivity and a true sense of compassion.”

While activists have praised the government’s action, they warn that the actual number of illegal adoptions may be in the thousands.

Fergus Finlay, head of child protection charity Barnardos, told RTE that an investigation should examine at least 150,000 adoptions. Finlay said he would be “amazed” if at least 10 percent of those cases were not found to be illegal.

Others such Claire McGettrick of the Adoption Rights Alliance, echoed the need to examine all adoptions, saying falsification of records didn’t only happen out of registered adoption societies.

“We’d definitely argue you’re talking a drop in the ocean here,” McGettrick said.

For now though, the prime minister said the government is focused on providing the identified people with “the information that they should’ve always had.”

“They’re looking for information about their identities and they want to know who they are, they want to know what their birth story is,” Varadkar said.