Royston Cave was discovered by accident in 1742 by workmen erecting a bench in the butter market above. A millstone was found in the ground which, when lifted, uncovered a vertical, well-like shaft. Toeholds had been cut into the chalk to form steps. A small boy volunteered to make the first descent and he found the cave to be more than half filled with earth and debris.
In the expectation of finding treasure, the shaft was enlarged and the cave was emptied, uncovering extensive carvings in the lower part of the chamber. No scientific archaeological investigation was made at the time but according to the Rev. G. North, who visited the cave shortly after its discovery, the contents included a skull, some decayed bones, fragments of a small drinking vessel and an unmarked piece of brass.