The first Cornish hedges appeared, enclosing land for cereal crops.
In 878 Doniert, king of the Cornish, was drowned in the River Fowey. Doniert's Stone stands in St. Cleer parish. This comprises of the stumps of two 9th century stones bearing Latin inscriptions and intricate patterns
The Early Bronze Age between 2,400 and 1,500BC saw the introduction of metal working. The use of bronze exploited Cornwall’s natural resources of tin and copper.
https://www.cornwalls.co.uk/history/ancient
https://www.cornwalls.co.uk/history/ancient/stones.htm
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By the middle of the ninth century, Cornwall had fallen under the control of Wessex, but it kept its own culture. In 1337, the title Duke of Cornwall was created by the English monarchy, to be held by the king's eldest son and heir. Cornwall, along with the neighbouring county of Devon, maintained Stannary institutions that granted some local control over its most important product, tin, but by the time of Henry VIII most vestiges of Cornish autonomy had been removed as England became an increasingly centralised state under the Tudor dynasty. Conflicts with the centre took place with the Cornish Rebellion of 1497 and Prayer Book Rebellion of 1549.
https://en.wikipedia.org/wiki/History_of_Cornwall
https://en.wikipedia.org/wiki/Duke_of_Cornwall>>13899491
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Looks like a [P]hoenician spot.