Former President Barack Obama is leading the tributes to his grandmother and family matriarch following her death at the age of 99. Sarah Obama, Barack’s step-grandmother, was receiving treatment for an undisclosed illness in Western Kenya when she passed away on Monday. The ex-president posted a photo of the two of them together, with the caption: “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. We will miss her dearly, but we’ll celebrate with gratitude her long and remarkable life.” Sarah became famous in Kenya when her step-grandson, then a U.S. senator, paid her a visit in 2006. He also visited in 2015, when he became the first U.S. president to visit Kenya, and in 2018 after he left office. Kenyan President Uhuru Kenyatta called her death a “big blow to our nation.”