Miniatures are a subset of portrait paintings, and within miniatures is yet another, more obscure, subset: paintings of a left eye, or a right eye, amid little else. Dubbed “lovers’ eyes” by a canny antiques dealer, nearly all miniature eye portraits were painted with watercolor on ivory in the late-eighteenth and early nineteenth century. They were set in rings, lockets, brooches, toothpick cases, and the like, and gifted between lovers. Luminous, exquisite, and fragile (a drop of water might wash away the tiny brushstrokes), lovers’ eyes did not mean, as it might seem, “I have my eye on you”, but rather, “You have my heart, and here’s my eye to prove it”.

By the 1770s, miniature portraits were ubiquitous, and easily commissioned. One scholar suggests that it was artists’ boredom that led to the fad for isolated eyes, but the more compelling explanation is their clients’ erotic whimsy. A disembodied eye is only identifiable to an intimate, making it an unusually private kind of token, the exchange of which would have been amenable to couples whose understandings were necessarily secret, and also, perhaps, to couples whose understandings weren’t secret, but who appreciated the sexual frisson of code talk.

The fad for eye miniatures in England began when the future King George IV fell in love with Maria Fitzherbert, a woman unsuitable to his rank (widowed, Catholic, a commoner). He covertly sent her a painting of his eye with a proposal to marry. The overture was welcome, and after a long and tumultuous relationship, he was buried with a painting of her eye.

A literal-minded person might protest: Why is it sexy to wear a lover’s eye? Isn’t an eye pinned on a dress, or in a locket, looking in an unromantic direction, i.e., not at the lover? And what about the whiff of monstrosity in donning a third eye? As in many things with love, sharp scrutiny withers the sentiment.

The best way to understand lovers’ eyes, it turns out, is via another contemporaneous miniature, which is pointedly not an eye, but a tiny painting of two breasts. Beauty Revealed is the anomaly that lays bare the pattern. The self-portrait was gifted by one of the most famed miniaturists of her day, Sarah Goodridge, to her lover, the politician Daniel Webster. It’s a heady gift of flesh, swathed like the baby Jesus, both delicate and campy, the tiniest of flaws (the mole, the asymmetry) in service of beauty made more perfect. Here I am. Don’t forget. Take me. Goodridge must have decided an eye was entirely too coy and cryptic.

The collection of eye miniatures below comes courtesy of the Philadelphia Museum of Art.