It was during the Iron Age that the Roman influence reached Southern Britain owing to the trading links. Towards the end of the second century BC, Roman influence extended into the Western Mediterranean and Southern France. As a result of this, a growing contact is formed between Britain and the Roman world across the English Channel. Britain was indirectly linked into the Roman trading network.
At first they were confined to trade limited Roman luxury goods, like wine, which were probably exchanged for slaves, minerals and grains through sites like Hengistbury Head in Dorset and Mount Batten near Plymouth in Devon. Gradually, Roman influence grew in Britain owing to trade. Britain was mostly comprised of small Iron Age communities – primarily Agrarian and tribal with enclosed settlements, at the time of the Roman arrival.
As a result of Southern Britain sharing its culture with Transalpine Gaul, trading between the two lands intensified. Evidence of these trading activities were found in Southeast Britain, of Gallo-Belgae coinage. The Romans, who were after Gaul did not find this connection approving. Therefore, the Romans landed in Britain to look into the atmosphere. It was when Julius Caesar undertook two expeditions in 55 BC and 54 BC as part of his conquest of Gaul, that the first direct Roman contact with Britain took place.
This was because he believed that Britain was helping the Gallic resistance. A thriving trade between Southern Britain and the near continent was established after the conquest of Gaul. This is archaeologically evidenced through the imports of wine and olive oil.
Romans built diplomatic relations with a number of tribes in addition to the trade links, and may have exerted a considerable amount of political influence before the Roman conquest of Britain in 43 AD.