In 1785, when Maria Anne Fitzherbert opened a love letter from her admirer, Prince George of Wales, she wasn’t expecting to find an eye, gazing intently back at her.

The British prince was lovesick—and desperate. He’d fallen hard for Fitzherbert, but their courtship had been disastrous: Royal laws forbade a Catholic widow like his beloved from becoming a monarch. To make matters worse, the upstanding Fitzherbert had fled the country after the prince’s first proposal, in an attempt to avoid controversy.

But the prince was determined, and on November 3rd, he penned a passionate letter begging again for her hand in marriage. This was no ordinary proposal, though—it also contained a rare, spellbinding gift. “I send you a parcel,” George wrote in the letter’s postscript, “and I send you at the same time an Eye.”

Indeed, the package contained a very small, potent painting of George’s own right eye, floating uncannily against a monochromatic background. No other facial features anchored it, save a barely-there eyebrow. All focus was on the composition’s core, where a dark iris gazed ardently from behind a soft, love-drunk lid.