The miraculous beam

A beam too short at dusk was a foot too long by morning.

While the Norman priory at Twynham was being built, the workmen found that a beam hoisted into place was too short, so they went home for the night to work out what to do. Next morning the beam was a foot longer than it needed to be. Since the church was being dedicated to Christ, the builders believed he had stretched it himself. Wikipedia notes that both names already appear together in a grant of 954, so the renaming story cannot be literally true. The town took the name Christchurch in honour of the event, and the beam is still shown in the priory.