Telling the time by the sun’s position in the sky – especially in cloud-prone Britain – seems unlikely ever to have been reliable. But the number of sundials scratched into the walls of churches shows it was once the best or perhaps the only method available.
It was important to the medieval church because mass has to be said at sunrise, mid-morning, noon, mid-afternoon and sunset. So the scratch dial or mass dials still seen on the south side of churches have lines, not for the hours, but so the faithful could tell when these prayers should be said. They are mostly dated between 1100 and 1600, when Henry VIII’s reformation made them redundant.
You may not have heard of the British Sundial Society but these enthusiasts are compiling a register of these mass dials so they can be properly recorded. There are hundreds remaining, sometimes several on each church, characterised by holes in the middle where a stick was placed to cast a shadow on to the lines marking the times for prayer.
With a suitable stick, most still work, but an unexplained anomaly is that some are not on south walls but elsewhere in churches, sometimes on reused stone and otherwise simply religious graffiti.
