Former President Barack Obama’s step-grandmother died Monday in Kenya at the age of 99. Obama shared news of her death on social media.

Sarah Obama, who was known as "Mama Sarah,” died at a hospital in the city of Kisumu. She had been treated for natural diseases, and her death was not related to COVID-19, her daughter told the Associated Press.

Mama Sarah was said to have played a major role in raising the former U.S. President’s father, Barack Obama Sr., who lived from 1934 to 1982.

Former President Barack Obama reminisced on Instagram about the time he spent with Mama Sarah and what he learned from her about life and his father. 

"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," Obama posted on Instagram.

"Born in the first quarter of the last century, in Nyanza Province, on the shores of Lake Victoria, she had no formal schooling, and in the ways of her tribe, she was married off to a much older man while only a teen. She would spend the rest of her life in the tiny village of Alego, in a small home built of mud-and thatch brick and without electricity or indoor plumbing. There she raised eight children, tended to her goats and chickens, grew an assortment of crops, and took what the family didn’t use to sell at the local open-air market.

“When I first traveled to Kenya to learn more about my heritage and father, who had passed away by then, it was Granny who served as a bridge to the past, and it was her stories that helped fill a void in my heart,” he continued.

Mama Sarah was known for her work in her village by promoting education for the girls and the orphans, the AP noted. She had her own foundation called the Mama Sarah Obama Foundation that provided orphans with school supplies, uniforms, school fees and some medical needs. This led to her receiving the United Nations’ Pioneer Award in 2014 for her educational efforts. 

“If a woman gets an education she will not only educate her family but educate the entire village,” she said in 2014.

In 2015, Barack Obama became the first U.S. president to visit the country. 

"We will miss her dearly, but celebrate with gratitude her long and remarkable life," Barack Obama posted on Instagram. 

Former president Barack Obama in a new memoir voices deep respect for India's former prime minister Manmohan Singh, seen here in a 2013 White House meeting Former president Barack Obama in a new memoir voices deep respect for India's former prime minister Manmohan Singh, seen here in a 2013 White House meeting Photo: GETTY IMAGES NORTH AMERICA / WIN MCNAMEE