Decades before they would serve together on the Supreme Court, William Rehnquist and Sandra Day O’Connor were engaged in a different type of courtship.

The two grew close while attending Stanford Law School — they regularly shared notes and eventually became a couple. Although Sandra Day, as she was known then, eventually broke up with Rehnquist and married a different Stanford Law classmate, John O’Connor, an author recently revealed to NPR that she first turned down a marriage proposal from Rehnquist, the future chief justice, in the early 1950s.

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Rehnquist graduated a semester early and went to Washington for a Supreme Court clerkship. In a letter to Day, who had already begun dating John O’Connor, Rehnquist said he wanted to see her and discuss “important things,” author Evan Thomas told NPR on Wednesday.

Supreme Court Associate Justice Sandra Day O'Connor and US Chief Justice William H. Rehnquist. (Photos by Mark Wilson/Getty Images; Joyce Naltchayan/AFP/Getty Images) (Mark Wilson; Joyce Naltchayan/Mark Wilson/Getty Images; Joyce Naltchayan/AFP/Getty Images)

Rehnquist later wrote: “To be specific, Sandy, will you marry me this summer?”

Thomas discovered the letters while conducting research for his upcoming book, “First,” a biography of O’Connor, who was nominated by Ronald Reagan to the nation’s highest court in 1981.

O’Connor’s son, Jay, told NPR that news of the proposal was a surprise to his family members, though they had known that his mother had dated Rehnquist.

“Dating was pretty innocent in the ’50s,” Jay O’Connor told NPR. He added that “multiple men proposed to my mom when she was in college and law school, and ultimately my dad was the one who was the real deal.”

She would instead end up marrying John O’Connor, becoming Sandra Day O’Connor in 1952. While her romance with Rehnquist never flourished, they remained close friends until he died in 2005; they even became neighbors at one point.

“It was just an amazing accident of history that . . . my mom and her friend and law school classmate ended up on the Supreme Court together,” her son told NPR. “Not only did they have a wonderful working relationship for over 25 years on the court, they had a wonderful friendship their entire life.”

This month, O’Connor announced that she was withdrawing from public life after being diagnosed with dementia. She served on the Supreme Court from 1981 until 2006.

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