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.

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.