The number of holy wells recorded before the Domesday Book is very small, but Chalgrave has one of them, called Kimberwell, a corruption of its old name, recorded as early as 926, in the form (to) Cynberge wellan, ‘(to) Cyneburg’s Well’. The well was probably dedicated to St. Cyneburg, abbess of Castor (d. 680), and in The Living Stream (1995) James Rattue speculates that she may have been born at Chalgrave.
One of many Anglo-Saxon royal saints, Cyneburg was the daughter of the pagan King Penda of Mercia. According to the Venerable Bede, she was married to Alcfrith, the son of King Oswiu of Northumbria. They lived a chaste life together, if not from the first, for many years. It is uncertain whether Alcfrith then died or entered a monastery, but after a time, Cyneburg was free to leave Northumbria and return to her own land. She founded a convent in fen country at a place subsequently known as Cyneburg-cestre, ‘Cyneburg’s Town’, now Castor, Huntingtonshire and Peterborough, where the parish church is dedicated to her. Although forgotten elsewhere, she was long remembered around Castor in local tradition as ‘Lady Coneyburrow’ and ‘Lady Ketilborough’.