From about 1200 BCE there is clear evidence for agriculture in the south of nowadays England; the farms consisted of circular huts in groups with small oblong fields and stock enclosures. This type of farm became standard in Britain down to and into the Roman period. From the 8th century BCE onward, expansion of continental Urnfield and Hallstatt groups brought new people (mainly the Celts) to Britain; they came at first, perhaps, in small prospecting groups, but soon their influence spread, and new settlements developed. Some of the earliest hill forts in Britain were constructed in this period (e.g., Beacon Hill, near Ivinghoe, Buckinghamshire; or Finavon, Angus); though formally belonging to the late Bronze Age, they usher in the succeeding period.
Before the Roman conquest of Britain in the 1st century CE, the island was not significant in the history of Western civilization, except perhaps for it's tin mines for which the Phoenicians are supposed to have visited Britain. The first detailed description of Britain and its inhabitants was written by the Greek merchant Pytheas, who explored the coastal region about 325 BCE. He was a merchant from the Greek colony at Marseilles (Massilia) and he sailed round the 'Northern Seas' and put Britain firmly on the map. His own words have not survived but other classical writers often quote him. He sailed from Cadiz in Spain through the Straits of Gibraltar, north by Ushant to Cornwall, Devon and Ictis, the tin port. He then sailed right round Britain describing the inhabitants and the weather.
He says that the British tribes were independent, ruled by kings and preserved their ancient customs. They used chariots in war. Their dwellings were humble, made of timber and thatch; they stored grain in covered pits and granaries and brewed a drink made from corn and honey.
As a merchant, Pytheas knew much about the tin trade.
'The inhabitants of Britain who live in the south-west are especially friendly to strangers and from meeting foreign traders have adopted civilized habits. It is these people who produce the tin, cleverly working the land that bears it. They dig out the ore, melt it and purify it. They then hammer the metal into ingots like knuckle-bones and transport them to an island off the coast called Ictis, for the channel dries out at low tide and they can take the tin over in large quantities on their carts. Merchants purchase the tin from the natives there and ship it back to gaul.'
Little trace, however, has been left of the language or civilization of the original inhabitants, other than megalithic monuments, such as Stonehenge, which date from the Bronze Age (circa 2000BCE). Between the Bronze Age and about the 6th century BCE, Britain was inhabited by Picts and European Celts, who periodically invaded the British Isles until the 1st century BCE.