Human presence here is intermittent for most of its length. Palaeolithic finds are scattered and rare - handaxes from Constantine, Coverack, Lanhydrock, the Lower Leha biface dated to perhaps 225,000 BCE. The Last Glacial Maximum pushed people out of Britain entirely. They came back around 15,500 years ago, and ancient DNA tells the story in layers: first a population related to a 15,000-year-old individual from the Goyet Caves in Belgium, then a second wave related to a hunter-gatherer from Villabruna in Italy whose lineage came to dominate the British Mesolithic. By the Mesolithic, from around 9,660 BCE, Cornwall had permanent residents - semi-nomadic hunter-gatherers who left thousands of flint scrapers around Dozmary Pool on Bodmin Moor, the moor's only permanent lake, possibly a hide-processing site. At Gwithian they prepared seal skins with bevelled pebbles, perhaps to stretch over wooden frames as coracles. Decorated pebbles incised with parallel lines from Trevose Head and Poldowrian are among the rare Mesolithic art objects of Britain.

Around 4,000 BCE the Neolithic arrived from the European mainland - not as an idea adopted by hunter-gatherers but as people, Early European Farmers descended from populations that took the Mediterranean route from Anatolia. Genetic studies show only minimal mixing with the existing inhabitants. The newcomers brought cattle, sheep, pigs, wheat, barley, pottery, and a habit of building monuments on a scale Cornwall had never seen. They quarried greenstone from West Penwith and shaped it into beautiful axe heads that were traded as far as Wessex, East Anglia, and Yorkshire. They threw up tor enclosures - vast walled spaces like Carn Brea, where hundreds of leaf-shaped flint arrowheads testify to an attack by archers and the fire-damaged buildings to its conclusion. They left the dead in chambered tombs called quoits, where capstones of granite still balance impossibly on uprights at Lanyon, Zennor, Mulfra, and Trevethy. At Hendraburnick someone carved over a hundred cup-marks into a fallen greenstone slab and smashed nearly 150 kilograms of quartz around it - perhaps for the way quartz reflects firelight and moonlight, illuminating rock art in the dark.

The Bronze Age, beginning around 2,400 BCE with the Bell Beaker migration that brought yet another major influx of people from the European mainland, gave Cornwall what would define it for the next four thousand years: metal. Cornish tin, alloyed with copper to make bronze, was exported across Britain, to Ireland, to mainland Europe, and as far as the Eastern Mediterranean. The peninsula became a node in a trading network that reached the palaces of the Aegean. Gold went the same way. Around 1,500 BCE an agricultural revolution swept the south-west - field boundaries appeared, roundhouse villages multiplied, and farming became settled rather than occasional. On Bodmin Moor and West Penwith, hundreds of Bronze Age round stone hut foundations still mark the ground. Stone circles like the Hurlers, the Merry Maidens, and Boscawen-Un went up, alongside menhirs - the Pipers, the Blind Fiddler, the Old Man of Gugh on Scilly - and ranks of stone rows on the moors whose purpose remains debated.

By the Iron Age, around 800 BCE, the climate was colder and wetter. Iron replaced bronze in everyday tools, and the peninsula bristled with defensive sites - rounds (small embanked enclosures), hillforts on the high ground, and cliff castles cut off by ramparts where the land met the sea. Chun Castle near Pendeen, Castle-an-Dinas above St Columb, and the courtyard houses of Carn Euny suggest a population that had grown, divided itself into local power centres, and built to defend against neighbours. Roundhouses sometimes clustered into proper villages. Cornish tin was still travelling - the Greek explorer Pytheas of Massalia, voyaging around 325 BCE, recorded an island he called Ictis where tin was traded with foreign merchants. The arrival of the Romans in 43 CE conventionally closes the prehistoric period, though in Cornwall the Roman presence was always lighter than further east, and the deep continuities of stone, sea, and metal carried on.

What survives is not random. Cornwall's geology and acidic soils destroy organic remains - bone, hide, wood, plant fibre - and so the picture is dominated by stone. But its peripheral position meant successive cultures often built around earlier monuments rather than over them, and its granite uplands have never been ploughed flat. Bodmin Moor and West Penwith preserve a Bronze Age landscape of huts, fields, cairns, and circles almost intact. The Isles of Scilly add another layer - terraced hillsides, entrance graves found nowhere else in Britain except South-West Scotland, Brittany, and parts of Spain. Walk a coast path or a moorland track here and you are likely to step on something prehistoric without knowing it. The handaxe at Lower Leha is one end of the timeline. The roundhouse foundations of Bodrifty are nearer the other. Between them, two thousand centuries of people made themselves at home on this granite finger of Britain, and then left.