Katherine Harvey, a historian of medieval medicine, started from the usual assumption — that the Middle Ages explained mental illness as demonic possession and had no vocabulary for what we now call mental health. Then she read the medical texts instead of the saints’ lives. What she found was a sophisticated argument that mental wellness was the foundation of physical health.
Under humoral medicine, health meant balancing blood, phlegm, black bile, and yellow bile. The main lever for that was the “six non-naturals” — diet, exercise, sleep, air, and the emotions. Emotional regulation wasn’t a moral question. It was medical maintenance.
- Anger was thought to “consume the body swiftly, so that the man meets a short end”; one chronicler blamed Henry I’s final illness on a quarrel with his daughter
- Chronic strain was recognized as lethal: a bent bow, a manuscript image warns, cannot survive continual stress — household disputes could “shorten a person’s years”
- Monks burned out at rates the essay documents in detail. Matthew, precentor of Rievaulx, complained of no “peace in my bones”; Alexander de Langley at St Albans had breakdowns attributed first to overwork, then to overstudy
- The Florentine merchant Francesco Datini, who said fate willed he should “never know a whole happy day,” is the essay’s central anxious case — fretting about ships, plague, and elections
- King Duarte of Portugal wrote movingly of a lifelong “melancholic humour” that began while he governed during a plague outbreak
The remedies come in two registers. First the curio cabinet: saffron to provoke joy (one Welsh recipe warns against eating so much you “die of happiness”), ostrich liver for melancholy, and Hildegard of Bingen advising an onyx held in the mouth. Then the part that reads like a modern prescription — Taddeo Alderotti treated the lord of Ferrara’s two years of melancholy and insomnia with walks, beautiful things to look at, songs he liked, and news of profitable markets.
The rest of the essay is essentially social prescribing, five centuries early:
- Music and storytelling, which Bologna’s city government funded for a dying man because “constant worrying deprives individuals of their vital breath”
- Gardens, praised for scent, water, and the combination of mental relaxation with physical exercise
- Outdoor walking, defended by the 15th-century physician John Mirfield as good for body, soul, and mind at once
- Pets — cats, dogs, birds, and, in the case of the bishop of Durham, monkeys kept “to ease the burden of his worries”
- Cheerful books. One ailing friar was ordered to stop reading martyrdom stories “for the sake of his health”
- For the elderly: conversation, storytelling, and maths problems, since “the exercise of the mind increases its strength to such an extent that many people are cured of their ills through sheer delight”
The sharpest part is the closing move. Harvey notes the prohibitive cost of care for many people today, the side effects of widely prescribed psychiatric drugs, and the argument that diagnostic labels are overused — then takes only the modest lesson: anxiety and depression are not a modern fad but a perennial human problem, and prevention, connection, and daily life belong inside the treatment, not outside it.