“Madly in love?” “Burning with passion?” “Lovesick?” These phrases are familiar in contemporary popular culture, which celebrates love as a sublime experience. But romantic love was once perceived quite differently, as a real sickness in search of a cure. The fashionable young men and women in Renaissance miniature portraits suffer from this disorder, termed “erotomania,” or love melancholia. They lock their gazes intently with our own, expressing a sort of delicious misery, as they revel in their suffering. The emotional intensity of such portraits, which was calculated to instigate a palpable physical response in the viewer, was not intended for strangers, but for one person only, the lover. When we gaze at these long dead faces, we assume the role of modern voyeurs, bridging the centuries as participants in a form of private, pictorial lovemaking.