The key to the heart: custody, trust and possession in love

A key opens and closes, protects and hands over. It is hardly surprising that it has become a metaphor for love: to entrust someone with the key to one's heart means granting them access to what is most intimate. This image, which we find today on pendants and cards, has roots in Roman legal practice, in medieval poetic allegory and in everyday objects exchanged between lovers.

The keys of the Roman house

In the Roman world the keys of the house had a precise meaning. The wife, as mother of the family, was the keeper of the storeroom and household goods, and the keys represented this responsibility. The reverse gesture signified separation: taking the keys back from a woman amounted to dissolving the union. Cicero, in the second Philippic, sarcastically recalls that Mark Antony had taken the keys back from the actress Cytheris, using the formula of divorce.

In this context the key is not yet a romantic symbol, but a legal and social sign of the trust granted. It was precisely this link between key, house and couple that prepared the ground for later romantic meanings, in which the key to the heart becomes the sentimental equivalent of the keys to the shared home, handed to the one who comes to belong there.

The heart under lock and key

The shift to the romantic metaphor is very clear in the Roman de la Rose, the allegorical poem begun by Guillaume de Lorris around 1230. After striking the lover with his arrows, the God of Love receives his feudal homage and locks his heart with a little golden key, so that no one else may enter it. The heart thus becomes a strongbox guarded by Lord Love, and the lover his faithful vassal.

In late medieval Germany the so-called Minnekästchen circulated, small wooden caskets decorated with courtship scenes and fitted with a lock, which were given as love tokens. These objects show how the idea of keeping a secret or a gift of love under lock and key had also entered the material culture of the time, well beyond the verses of the poets.

Pendants, padlocks and promises

In the nineteenth century sentimental jewellery gave ample space to keys and padlocks: heart-shaped lockets with a tiny lock, bracelets with dangling keys, pendants containing portraits or locks of hair. The closed object guarded the image of the beloved, and the key stayed with the giver or the receiver, depending on the message to be conveyed.

Much more recently the custom of love locks has spread, padlocks fastened to bridges and railings with the key thrown into the water. In Rome the fashion caught on at Ponte Milvio around the middle of the 2000s, while in Paris the weight of the padlocks led the authorities to remove the panels of the Pont des Arts in 2015. It is a modern custom, but it takes up a very ancient image.

From the keys of the Roman matron to the golden key of the God of Love, from medieval caskets to padlocks on bridges, the key has expressed a constant idea: to love means to entrust and to guard. The symbol unites the trust of one who opens up to another and the more ambiguous desire to make what one loves exclusive and safe.