Roman-inspired writing? David Gowans / Alamy Stock Photo

Scottish fisherman pulled up a rare catch near Aberdeen earlier this year: a large stone etched with geometric markings. It was a Pictish symbol stone, with a meaning and age as enigmatic as the people who made it. Now it seems that the Picts began carving their symbols much earlier than we had thought, possibly influenced by the Romans – which bolsters the idea that the symbols are remnants of an ancient writing system.

The Picts were a coalition of tribal kingdoms inhabiting the far north of what is now Scotland, between about …