WASHINGTON (AP) — On election night 2008, as Barack Obama sat nervously in a Chicago hotel suite and awaited news on whether he would become the country’s first Black president, his mother-in-law was by his side.

“Are you ready for this, Grandma?” Obama asked Marian Shields Robinson, who years earlier had doubted that he and her daughter, Michelle, would last.

Six months, tops, she had predicted.

“Never one to overemote, my mom just gave him a sideways look and shrugged, causing them both to smile,” Michelle Obama wrote in her memoir, “Becoming.” “Later, though, she’d describe to me how overcome she’d felt right then, struck just as I’d been by his vulnerability. America had come to see Barack as self-assured and powerful, but my mother also recognized the gravity of the passage, the loneliness of the job ahead.”

She continued: “The next time I looked over, I saw that she and Barack were holding hands.”

The union of Barack and Michelle Obama, the 20-something lawyers who met one summer while working at a Chicago law firm, endured and made history. In her own way, Mrs. Robinson would, too.

She died peacefully on Friday, the former first lady and her brother, Craig Robinson, and their families announced in a statement.

“There was and will be only one Marian Robinson,” they said. “In our sadness, we are lifted up by the extraordinary gift of her life. And we will spend the rest of ours trying to live up to her example.”

Besides being the mother of the nation’s first Black first lady, Mrs. Robinson was also unusual for being one of the few in-laws who lived at the White House with the president and his immediate family.

Until January 2009, Mrs. Robinson had lived her entire life in Chicago. She was a widow and in her early 70s when Obama was elected in 2008 and resisted the idea of starting over in Washington. President Obama said the family suggested she try Washington for three months before deciding. The first lady enlisted her brother to help persuade their mother to move.

“There were many good and valid reasons that Michelle raised with me, not the least of which was the opportunity to continue spending time with my granddaughters, Malia and Sasha, and to assist in giving them a sense of normalcy that is a priority for both of their parents, as has been from the time Barack began his political career,” Mrs. Robinson wrote in the foreword to “A Game of Character,” a memoir by her son, formerly the head men’s basketball coach at Oregon State University.

“My feeling, however, was that I could visit periodically without actually moving in and still be there for the girls,” she said.

Mrs. Robinson said her son understood why she wanted to stay in Chicago, but still used a line of reasoning on her that she would use on him and his sister. He asked her to think of the move as an opportunity to grow and try something new.

“As a compromise, I opted to move to the White House after all, at least temporarily, while still reserving lots of time to travel and maintain a certain amount of autonomy,” she wrote.

Granddaughters Malia and Sasha were just 10 and 7, respectively, when they started to call the executive mansion home in 2009 after their dad became president. In Chicago, Mrs. Robinson had become almost a surrogate parent to them during the presidential campaign. She retired from her job as a bank secretary to help shuttle them around.

At the White House, she was a reassuring presence, and her lack of Secret Service protection made it possible for her to accompany them to and from school daily without fanfare.

“I would not be who I am today without the steady hand and unconditional love of my mother, Marian Shields Robinson,” Michelle Obama wrote in her memoir. “She has always been my rock, allowing me the freedom to be who I am, while never allowing my feet to get too far off the ground. Her boundless love for my girls, and her willingness to put our needs before her own, gave me the comfort and confidence to venture out into the world knowing they were safe and cherished at home.”

Her White House life was not limited to caring for her granddaughters.

Mrs. Robinson enjoyed a level of anonymity that the president and first lady openly envied, allowing her to come and go from the White House as often as she pleased on shopping trips around town, to the president’s box at the Kennedy Center and to Las Vegas or to visit her other grandchildren in Portland, Oregon. She gave a few media interviews but never to White House press.

She attended some White House events, including concerts, the annual Easter Egg Roll and National Christmas Tree lighting, and was a guest at some state dinners.

White House residency also opened up the world to Mrs. Robinson, who had been widowed for nearly 20 years when she moved to a room on the third floor, one floor above the first family.

She had never traveled outside the U.S. until she moved to Washington, taking her first flight abroad on Air Force One in 2009 when the Obamas visited France. She joined them on a trip to Russia, Italy and Ghana later that year, during which she got to meet Pope Benedict, tour Rome’s ancient Colosseum and view a former slave-holding compound on the African coast.

She also accompanied her daughter and granddaughters on two overseas trips without the president to South Africa and Botswana in 2011, and China in 2014.

Craig Robinson wrote that he and his parents doubted whether his sister’s relationship with Obama would last, though Fraser Robinson III and his wife thought the young lawyer was a worthy suitor for their daughter, also a lawyer. Craig Robinson and his parents were sitting on the front porch of their Chicago home one hot summer night when Obama and his sister stopped by on their way to a movie.

Her parents exchanged knowing glances as soon as the couple departed. “Too bad,” Mrs. Robinson said. “Yep,” answered Fraser Robinson. “She’ll eat him alive.”

Craig Robinson wrote that his mother gave the relationship six months. Barack and Michelle Obama tied the knot on Oct. 3, 1992 and have been married for 31 years.

Marian Lois Shields Robinson was born in Chicago on July 30, 1937. She attended two years of teaching college, married in 1960 and, as a stay-at-home mom, stressed the importance of education to her children. Both were educated at Ivy League schools, each with a bachelor’s degree from Princeton. Michelle Obama also has a law degree from Harvard.

Fraser Robinson was a pump operator for the Chicago Water Department. He had multiple sclerosis and died in 1991.

Besides the Obama family, Mrs. Robinson is survived by her son, Craig, his wife, Kelly, and their children Avery, Austin, Aaron and Leslie.