On this day in 1961, a Buckingham Palace statement announced that Charles, Prince of Wales, had become officially engaged to a young woman from Kings Lynn, Norfolk.
Charles had met Diana Spencer, now his fiancée, after going out with her eldest sister, Lady Sarah. Their engagement was commemorated with a large £30,000 diamond ring.
Despite a poor academic record, 20-year-old Diana had already become known for her outstanding community spirit - and this would continue to grow with her status.
Diana would become The Princess of Wales upon her marriage to Charles on July 9, 1981, before a television audience of 750m viewers.
At the time, it was widely billed as a "fairytale wedding".
The engagement announcement of February 24, 1981, would begin the near-constant media scrutiny of Diana which continued until her death in 1997.
This same press scrutiny would sensationalise Diana and Charles' divorce in the early-1990s, with tabloid reports of disputes and infidelities between the pair.
In retrospect, Charles and Diana's engagement announcement began a new era of relations between the Royals, the press and public - an era which will never quite be repeated again.
For this reason, memorabilia from this period has appreciating value attached to it and is eagerly sought-after by collectors.
Diana artefacts currently available on the market include signed photographs of Diana both alone and with Prince Philip; signed photos of Prince Charles with Diana; one with a baby Prince William; and one with both William and Harry.
At present, Diana autographs can command values anywhere from $4,000 to $20,000 or more.
But Royal memorabilia has a significance unmatched by media celebrities, and Diana's signature will only continue to accrue historical significance and value as future generations remember "The People's Princess".