Eunice Kennedy Shriver died at 2 a.m. Tuesday at a Cape Cod, Massachusetts hospital at the age of 88.
Shriver, the fifth of nine children, was the younger sister of President John F. Kennedy, the mother of Maria Shriver, and mother-in-law of California Governor Arnold Schwarzenegger.
The Shriver family issued a statement via Eunice's Web site Tuesday, memorializing their beloved matriarch.
"Inspired by her love of God, her devotion to her family, and her relentless belief in the dignity and worth of every human life, she worked without ceasing - searching, pushing, demanding, hoping for change," the family wrote.
The Hyannis Port, Massachusetts-based family praised Eunice for her considerable philanthropic achievements, most notably acting as a founder of the Special Olympics organization in the the 1960s.
"She was a living prayer, a living advocate, a living center of power," the family wrote. "She set out to change the world and to change us, and she did that and more. She founded the movement that became Special Olympics, the largest movement for acceptance and inclusion for people with intellectual disabilities in the history of the world. Her work transformed the lives of hundreds of millions of people across the globe, and they in turn are her living legacy."