They founded the hill forts, minted coins after the Roman fashion (king Cunobelinus, later co-memorised by William Shakespeare), introduced iron to Britain and the enhanced plough and thus advanced the system of agriculture.
They were warlike by nature and the natives were subdued or slain or had to flee and seek refuge in the mountains of the north and west or on the barren peninsula of Cornwall. Their society was quite highly developed. They combined the tribal society with the national alliances with the chieftains chosen from the most powerful family either by election or as a result of a bloody match. They loved fine arts of which the decorative knotworks are now the best known, boasting, they were especially keen on the personal fame and honour and a strong feelings of a warrior pride. Traditions were of a great importance in their culture. They had but a few laws of which the Weregild or “the ransom of blood” was the most important, money paid as a compensation for the slain, which prevented the ever-at-war society from being plagued by the perpetual raids and war for revenge.

The Celtic society was ruled over by a supreme warrior and his suit of premium warriors, who were his vassals in return for the cattle provided. There was also an essential role of the Druids. They were not the priests, as it is often misunderstood. They were more a sort of honoured scholars, untouchable and ever-respected judges and historians keeping the traditions and rites up. Were there a quarrel or a matter of disputation, a Druid was called to find the solution. However they gathered now and then (rituals of Beltane, the Celtic New Year…) around the henges, it is certain, that they built none. Also the stories of the mass human sacrifices are not factual.

In the 1st century BC the Roman Empire had reached its climax. Its borders were stretching as far as the Iberian Peninsula in the West, nowadays Germany in the North Africa to the South and nowadays Turkey in the East and its influence even further. Right the Romans (Tacitus, Diodorus Siculus or Caesar) give us the first written records on the Celts. In the year 55 BC emperor Gaius Iulius Caesar made an attempt co conquer Britain. The two main reasons were the wealth of the island (Britain was exporting crop and slaves), which was seen as a great and but a little defended source of supplies and the fact, that the Celts were aiding their Gaelic kindred resisting the Roman legions on the continent. The underestimated Britons put up a strong resistance and Caesar was forced to resolve the campaign and withdraw with a fixed yearly tribute. After his assassination in the year 44 BC the political situation in Rome changed. Soon the idea of Britain conquered and attached to the Empire as Provincia Britannia was renewed.
In the year 43 AD the emperor Claudius sent legions II. Augusta, IX. Hispana, XIV.