Sandra Day O'Connor, the first woman to serve as a justice on the U.S. Supreme Court, has died.

O'Connor was 93 years old.

She died in Phoenix, Arizona, on Friday "of complications related to advanced dementia, probably Alzheimer's, and a respiratory illness," the Supreme Court said in a statement.

O'Connor was appointed to the court in 1981 by President Ronald Reagan, and served nearly a quarter-century, retiring in 2006.

Chief Justice John Roberts, in a statement released by the court, said, "A daughter of the American Southwest, Sandra Day O'Connor blazed an historic trail as our Nation's first female Justice. She met that challenge with undaunted determination, indisputable ability, and engaging candor."