Craig Phadrig

Craig Phadrig is a wooded hill, 172 metres high, on the western edge of Inverness, overlooking the Beauly Firth. Its summit holds a vitrified fort: the stone walls have been heated so intensely that parts melted and fused into a glassy mass. The inner enclosure measures roughly 75 by 23 metres.

Radiocarbon dates from excavations in the 1970s suggest the inner wall was built in the 4th century BCE. Later finds, including metalworking tools and imported pottery, show that Picts used the site in the 7th century CE. It has often been linked with the Pictish king Bridei, visited by St Columba around 565, though that identification is disputed.

How such forts were vitrified is still argued over. Most archaeologists think timber-laced walls were burned, whether in attack, deliberate destruction or ritual, and experiments have produced some vitrification this way. Fringe writers have proposed exotic energy weapons, an idea with no supporting evidence.