The media did not treat her selection kindly, and as the New York Times noted: “Mutters were then heard from members of the fashion industry who felt a First Lady could ill afford such a sentimental gesture.”

This was, to be sure, a reflection of Carter’s modesty, frugality and practicality. (She also let it be known that she had brought her sewing machine to the White House.) But how she dressed was also a statement of how little interest she had in serving as a mere ornament to her husband’s presidency.

As Jimmy Carter put it in the statement he issued upon his wife’s death Sunday at the age of 96: “Rosalynn was my equal partner in everything I ever accomplished.”

That has been the case with other first ladies over the decades. But the unstated rule was that they were not to let the world know it.

Lady Bird Johnson’s audio diaries, featured in a riveting documentary now playing on Hulu, reveal her enormous influence — which is probably why she stipulated that they not be released until after her death. Even Eleanor Roosevelt played down the impact that her activism on the world stage had within her husband’s White House, saying: “I don’t think that the wife of a president should ever forget that it is he who is doing the important job.”

But Rosalynn Carter arrived at a time when women’s roles were changing at every level of society. And, according to Paul Costello, who was her assistant press secretary, the new first lady took to heart a bit of counsel from her own outspoken predecessor. “Betty Ford gave her wise advice: Do what you want to do because no matter what you do, you will be criticized,” Costello told me.

Still, the first lady was taken aback by the stir she created when, in the second year of the Carter presidency, she began showing up at Cabinet meetings and quietly taking notes.

“Jimmy and I had always worked side by side; it’s a tradition in southern families, and one that is not seen as in any way demeaning to the man,” she wrote in her autobiography. “I also think there was a not very subtle implication that Cabinet meetings were no place for a wife. I was supposed to take care of the house — period.”

It was not the only time she felt frustrated with the expectations that came with her role. Less than a month after the inauguration, she held her first solo news conference to announce the formation of a presidential commission on mental health — an issue that would become her biggest cause.

“The next morning when I picked up the Washington Post to read about it I found not one word about the commission or the press conference,” she recalled. This newspaper instead ran a story about how the Carters had established a policy against serving hard liquor at White House functions.

But Rosalynn Carter continued to press against the constraints, and in breaking her own path, she would make it easier for those who followed — including Hillary Clinton.

Rosalynn Carter traveled abroad and met with heads of state to discuss matters of substance, not for mere photo opportunities, and made it clear she was speaking for the administration in her public appearances. “Dinner guests at the White House have seen her interrupt the President — not rudely but unhesitatingly — usually to explain something more clearly than he had been doing,” the New York Times columnist Tom Wicker wrote in 1979.

It was also said, and she acknowledged, that the first lady kept a closer eye than her husband did on politics, though her instincts were not always perfect. As my colleagues Joe Holley and Kevin Sullivan noted in her obituary, her concern over Jimmy Carter’s plummeting poll numbers led her to urge him to shake up his Cabinet and deliver a “crisis of confidence” speech to the nation. The address was a disaster, branded the “malaise” speech, though the president himself never used the word.

When someone commented that the president didn’t seem bitter at his 1980 loss to Ronald Reagan, Rosalynn Carter retorted: “I’m bitter enough for the both of us.” But in the post-presidential years, the two of them, continuing to work as a team, found new endeavors, changing lives across this country and around the globe.

Now, he is in hospice care, and for the first time in 77 years without the woman who was, in all things, his equal partner. That she understood and demanded her place at his side was the real tribute of Rosalynn Carter’s love for Jimmy Carter — and for the country they together were determined to make a better one.