Sarah Obama, the step-grandmother of Barack Obama, has passed away. According to a statement, Sarah passed away around 4 a.m. local time on Monday morning (March 29) while being treated at the Jaramogi Oginga Odinga Teaching and Referral hospital in Kisumu, Kenya. She was at least 99 years old, ABC News reports.

“She died this morning. We are devastated,” her daughter Marsat Onyango told the Associated Press by phone.

Sarah, who was affectionately called “Mama Sarah” by family and friends, did not die from COVID-19, a family spokesperson said.

“Mama was sick with normal diseases she did not die of COVID-19,” Sheik Musa Ismail told ABC. He added that she tested negative for the virus and was sick for a week before going to the hospital.

Sarah was a well-known advocate for education for girls and orphans in her Nyang’oma Kogelo village. For decades, she supported orphans and raised some children in her home. She also founded the Mama Sara Obama Foundation, which worked to provide food, school supplies, school uniforms, medical care and more for children without parents.

“The passing away of Mama Sarah is a big blow to our nation. We’ve lost a strong, virtuous woman; a matriarch who held together the Obama family and was an icon of family values,” Kenya President Uhuru Kenyatta said.

Kisumu Governor Anyang Nyong’o added that Sarah will be remembered for her work to promote education and empowerment for orphans.

“She was a philanthropist who mobilized funds to pay school fees for the orphans,” he said, while offering his condolences to the family.

On Twitter, Barack mourned the loss of his grandmother. Sarah was the third wife of the former president’s grandfather and helped to raise his father, Barack Obama Sr.

“My family and I are mourning the loss of our beloved grandmother, Sarah Ogwel Onyango Obama, affectionately known to many as ‘Mama Sarah’ but known to us as ‘Dani’ or ‘Granny,’” he tweeted. “We will miss her dearly, but we’ll celebrate with gratitude her long and remarkable life.”

Barack wrote about his first time meeting Sarah and fondly referred to her as “Granny Sarah” in his 1995 memoir, Dreams from My Father: A Story of Race and Inheritance. The pair communicated with help from a translator and in 2008, Sarah attended Barack’s first presidential inauguration. In 2014, she was awarded the Women’s Entrepreneurship Day Education Pioneer Award from the United Nations for her work promoting education for girls.

In a 2014 interview with AP, Sarah recalled biking Barack’s father six miles every day to school in the larger town of Ngiya so that he could receive an education.

“I love education,” she told the outlet, adding, “If a woman gets an education she will not only educate her family but educate the entire village.”

Sarah Obama will be buried on Tuesday (March 30).