November 1977: Prince Charles meets Lady Diana for the first time at Althorp House, her 1,500-acre family estate in Northamptonshire, England. At the time, he was dating her older sister Sarah and had traveled up to join her for a shooting weekend. In a later interview, he’d recall “what fun she was” during this initial interaction.

February 1978: Charles and Sarah go on a ski weekend to Klosters in Switzerland (where they are captured by a photographer). It’s here where she allegedly meets a journalist whom she tells she wouldn’t marry Charles “if he were the dustman or the King of England.” Upset about her disclosure to the press, it’s said Charles ended their relationship soon after. However, both sisters remain in his circle, even attending his 30th birthday party in November at Buckingham Palace.

July 1980: Both Charles and Diana are invited to stay at their mutual friend Philip de Pass’s family home in Sussex for the weekend. There, Diana emphatically talks to Charles about the recent death of his beloved great-uncle, Lord Mountbatten. “The next minute, he leapt on me, practically,” she said according to the documentary Diana: In Her Own Words. “But then it sort of built up from there.”

September 1980: Cameras capture Diana at Balmoral, the royal family’s private estate in the Scottish Highlands. Just like that, the secret of their relationship is officially out.

February 1981: Prince Charles proposes to Diana at Windsor Castle. She says yes. At that time, it’s said the couple had only gone out a dozen or so times. Afterward, the press attention on the 19-year-old reaches a fever pitch. Although she handles much of it with grace, the New York Times reports that she once burst into tears at the wheel of her car. “I know it’s just a job they have to do, but sometimes I do wish they wouldn’t,” she said of all the photographers. She moves from a tiny apartment to Clarence House.

The couple formally announces their engagement to the world on February 24. When a reporter asks Charles if they are in love, he famously replies, “whatever ‘in love’ means.”

March 1981: Charles flies to Australia and New Zealand for five weeks, leaving his newly betrothed behind. She’s spotted crying at Heathrow airport upon his departure—not because she is sad, but because before he left, he had taken a phone call with Camilla Parker Bowles. “It just broke my heart,” she later recalled, according to Diana: In Her Own Words.