Jimmy Carter and Rosalynn Carter attend Former Governor of Georgia Jimmy Carter's fundraiser for his 1976 Presidential run at Royal Coach Inn Atlanta Georgia February 14, 1976
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Rosalynn Carter, Former First Lady, Humanitarian and Mental Health Advocate, Dies at 96

Former president Jimmy Carter called his wife his "equal partner in everything I ever accomplished."

Rosalynn Carter, who is credited with expanding the position of First Lady due to her prominent role in her husband Jimmy Carter's presidency, died on Sunday. She was 96.

Rosalynn Carter was diagnosed with dementia in May and recently entered hospice care at her home in Plains, Ga. According to a statement from the Carter Center, Jimmy and Rosalynn Carter's nonprofit organization, Rosalynn passed away with her family by her side.

Former president Jimmy Carter called his wife his "equal partner in everything I ever accomplished." The couple's 77-year marriage was the longest-running marriage of any first couple in U.S. history.

"She gave me wise guidance and encouragement when I needed it," Jimmy Carter said in a statement. "As long as Rosalynn was in the world, I always knew somebody loved and supported me."

 First Lady Rosalynn Carter circa the 1970s.

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Rosalynn was born Eleanor Rosalynn Smith in Plains, Ga. on Aug. 18, 1927.

Jimmy proposed to Rosalynn in 1945,  but she initially turned him down, explaining that she had made a promise to her father that she would finish college before getting married. After completing junior college, Rosalynn agreed to marry her lifelong love. The couple married on July 7, 1946. She was 18 and he was 21.

Rosalynn's dedication to mental health advocacy was a hallmark of her role as First Lady and the remainder of her life in public service. She served as an honorary chairperson on the President's Commission on Mental Health.

Along with Lady Bird Johnson and Betty Ford, Rosalynn Carter supported the Equal Rights Amendment. In 1978, she hosted the First Lady's Employment Seminar, which sought to inform communities on how to deal with unemployment.

The couple remained devoted to advocacy long after Carter's presidency, forming the Carter Center, dedicated to human rights and the alleviation of human suffering, and the Carter Work Project, a weeklong event for Habitat for Humanity.

Rosalynn also worked to fight poverty in her home state by joining the Policy Advisory Board of The Atlanta Project in 1991. She also founded Every Child By Two, a campaign to raise awareness of the importance of infant immunizations, the same year.

Alongside her husband, Rosalynn was awarded the Presidential Medal of Freedom in 1999. She was inducted into the National Women's Hall of Fame in 2001.

Rosalynn is survived by her husband Jimmy Carter, their four children, John William (born 1947), James Earl "Chip" III (born 1950), Donnel Jeffrey (born 1952) and Amy (born 1967), and 22 grandchildren and great-grandchildren.