LONDON (AP) — Auschwitz survivor Eva Schloss, the stepsister of teenage diarist Anne Frank and a tireless educator about the horrors of the Holocaust, has died. She was 96.

The Anne Frank Trust UK, of which Schloss was honorary president, said she died Saturday in London, where she lived.

Britain’s King Charles III said he was “privileged and proud” to have known Schloss, who co-founded the charitable trust to help young people challenge prejudice.

“The horrors that she endured as a young woman are impossible to comprehend and yet she devoted the rest of her life to overcoming hatred and prejudice, promoting kindness, courage, understanding and resilience through her tireless work for the Anne Frank Trust UK and for Holocaust education across the world,” the king said.

Born Eva Geiringer in Vienna in 1929, Schloss fled with her family to Amsterdam after Nazi Germany annexed Austria. She became friends with another Jewish girl of the same age, Anne Frank, whose diary would become one of the most famous chronicles of the Holocaust.

Like the Franks, Eva’s family spent two years in hiding to avoid capture after the Nazis occupied the Netherlands. They were eventually betrayed, arrested and sent to the Auschwitz death camp.

Schloss and her mother Fritzi survived until the camp was liberated by Soviet troops in 1945. Her father Erich and brother Heinz died in Auschwitz.

After the war, Eva moved to Britain, married German Jewish refugee Zvi Schloss and settled in London.

In 1953, her mother married Frank’s father, Otto, the only member of his immediate family to survive. Anne Frank died of typhus in the Bergen-Belsen concentration camp at the age of 15, months before the end of the war.

Schloss did not speak publicly about her experiences for decades, later saying that wartime trauma had made her withdrawn and unable to connect with others.

“I was silent for years, first because I wasn’t allowed to speak. Then I repressed it. I was angry with the world,” she told The Associated Press in 2004.

But after she addressed the opening of an Anne Frank exhibition in London in 1986, Schloss made it her mission to educate younger generations about the Nazi genocide. Over the following decades she spoke in schools and prisons, at international conferences and told her story in books including “Eva’s Story: A Survivor’s Tale by the Stepsister of Anne Frank.”

She kept campaigning into her 90s. In 2019, she traveled to Newport Beach, California to meet teenagers who were photographed making Nazi salutes at a high school party. The following year she was part of a campaign urging Facebook to remove Holocaust-denying material from the social networking site.

“We must never forget the terrible consequences of treating people as ‘other,’” Schloss said in 2024. “We need to respect everybody’s races and religions. We need to live together with our differences. The only way to achieve this is through education, and the younger we start the better.”

Schloss’ family remembered her as “a remarkable woman: an Auschwitz survivor, a devoted Holocaust educator, tireless in her work for remembrance, understanding and peace.”

“We hope her legacy will continue to inspire through the books, films and resources she leaves behind,” the family said in a statement.

Zvi Schloss died in 2016. Eva Schloss is survived by their three daughters, as well as grandchildren and great-grandchildren.