Sarah Obama, the matriarch of former president Barack Obama’s Kenyan family, died March 29 at a hospital in Kisumu, Kenya. She was thought to be in her late 90s.

Her daughter Marsat Onyango confirmed the death but did not provide a cause.

Mama Sarah, as Obama’s step-grandmother was called, promoted education for girls and orphans in her rural Kogelo village. The Mama Sarah Obama Foundation helped provide food and education to children who lost their parents — providing school supplies, uniforms, basic medical needs and school fees.

Sarah Obama was the second wife of Obama’s grandfather and helped raise his father, Barack Obama Sr. The family is part of Kenya’s Luo ethnic group.

The president often showed affection toward her and referred to her as “Granny” in his memoir, “Dreams from My Father.” He described meeting her during his 1988 trip to his father’s homeland and their initial awkwardness as they struggled to communicate which developed into a warm bond. She attended his first inauguration as president in 2009. Later, Obama spoke about his grandmother again in his September 2014 speech to the U.N. General Assembly.

In a 2014 interview with the Associated Press, she said that even as an adult, letters would arrive but she could not read them. She said she did not want her children to be illiterate, so she saw that all her family’s children went to school.

She recalled pedaling the president’s father six miles to school on the back of her bicycle every day from the family’s home village of Kogelo to the bigger town of Ngiya to make sure he got the education that she never had.

“I love education,” Sarah Obama said, because children “learn they can be self-sufficient,” especially girls who too often had no opportunity to go to school.

“If a woman gets an education she will not only educate her family but educate the entire village,” she said.

In recognition of her work to support education, she was honored by the United Nations in 2014, receiving the inaugural Women’s Entrepreneurship Day Organization Pioneer Award for education philanthropy.