Marian Robinson, the mother of former First Lady Michelle Obama, has died at the age of 86, the family announced Friday. She passed away peacefully that morning.

Michelle Obama shared a touching message on social media, calling her mother “my rock.” She wrote that Marian was always there when she was needed and a steady source of strength for the entire family.

Former President Barack Obama also paid tribute, describing his mother-in-law as truly one of a kind and saying the family feels grateful to have had her in their lives. He added that they will continue to honor her by living according to her example.

Born Marian Shields in 1937, she later married Fraser Robinson III, a World War II veteran who worked for the Chicago Water Department. Together, they raised Michelle and her brother Craig in a modest home on Chicago’s South Side.