St. Margaret's Well is a Grade II Listed Building, which is the model for Lewis Carroll's "Treacle Well" from Alice in Wonderland; this is a holy well dedicated to St Frideswide, patron saint of Oxford. She had fled to Binsey in a bid to escape marriage to a king of Mercia, whose pursuit of her was halted when he was struck blind at the gates of Oxford. Frideswide's prayers brought forth a healing spring, whose waters cured his blindness, and the spring was walled into a shallow well which became something of a focus for pilgrimage, the mediaeval sense of the word 'treacle' meaning 'healing unguent'. The well became a pilgrimage site in medieval times.
