Everyone knows that medieval people were dirty, smelly and largely indifferent to their own filth – or were they?

In fact, medieval physicians were well aware of the health benefits of good hygiene, and advice books told readers that keeping clean was the polite thing to do.

Dr Katherine Harvey of Birkbeck, University of London, reveals how all the evidence suggests that medieval people, both rich and poor, were much cleaner than we assume, making considerable efforts to keep their bodies, hair, teeth and clothes clean. Bodily parasites such as lice and worms were a big problem, but people did their best to prevent and treat infestations.

Only one section of medieval society actively embraced poor personal hygiene as a way of life: the extremely pious. There were numerous holy men and women who refused to bathe, never brushed their hair, or wore hair shirts swarming with lice – behaviour which their contemporaries greeted with a mix of admiration and revulsion.

Dr Katherine Harvey is a medieval historian based at Birkbeck, University of London. She is the author of Episcopal Appointments in England, c. 1214-1344 (Ashgate, 2014), and is currently writing books on The Episcopal Body in Medieval England (for OUP) and Sex and Sexuality in Medieval Europe (for Reaktion).