Eunice Kennedy Shriver, the sister of President John F. Kennedy and mother to California First Lady Maria Shriver, has died. She was 88.

Mrs. Kennedy Shriver passed away at 2 a.m. Tuesday morning at Cape Cod Hospital in Hyannis. She had suffered a series of strokes in recent years, the Associated Press reports.

One of nine children born to Rose and Joseph P. Kennedy Sr., Eunice was born in Massachusetts in 1921. A graduate of Stanford University, the achievement she will perhaps be best remembered for was helping to found the national Special Olympics organization, a cause to which she remained committed throughout her life.

Kennedy Shriver is survived by her husband of 56 years, Robert Sargent Shriver, five children, and many grandchildren.

The Shriver family expressed their grief in a statement to ET saying, "It's hard for us to believe: the amazing Eunice Kennedy Shriver went home to God this morning at 2 a.m.

"She was the light of our lives, a mother, wife, grandmother, sister and aunt who taught us by example and with passion what it means to live a faith-driven life of love and service to others. For each of us, she often seemed to stop time itself - to run another Special Olympics games, to visit us in our homes, to attend to her own mother, her sisters and brothers, and to sail, tell stories, and laugh and serve her friends. How did she do it all?

"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. She was a living prayer, a living advocate, a living center of power. 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.

"We have always been honored to share our mother with people of good will the world over who believe, as she did, that there is no limit to the human spirit. At this time of loss, we feel overwhelmed by the gifts of prayer and support poured out to us from so many who loved her. We are together in our belief that she is now in heaven, rejoicing with her family, enjoying the fruits of her faith, and still urging us onward to the challenges ahead. Her love will inspire us to faith and service always.

"She was forever devoted to the Blessed Mother. May she be welcomed now by Mary to the joy and love of life everlasting, in the certain truth that her love and spirit will live forever."

Eunice's family has set up a Web site, www.eunicekennedyshriver.org, that will post updates on her funeral arrangements and memorial service.