Before Julius Caesar invaded Britain, many Romans didn’t believe it existed. Julius Caesar was the first-ever Roman to invade Britain. He did it twice in the years 55 and 54 BC. Some Romans believed Britain to be just the foot of another huge northern continent. Others thought it was a place full of unbelievable riches, whilst most thought it just didn’t exist.
In the course of his Gallic Wars, Julius Caesar invaded Britain twice: in 55 and 54 BC. On the first occasion Caesar took with him only two legions and achieved little beyond a landing on the coast of Kent. The second invasion consisted of 628 ships, five legions and 2,000 cavalry. The Roman legion is the largest military unit of the Roman army, comprised 5,200 infantry and 300 equites (cavalry) in the period of the Roman Republic (509 BC–27 BC) and 5,600 infantry and 200 auxilia in the period of the Roman Empire (27 BC – AD 476). Caesar’s force was so overwhelming that the Britons did not dare contest Caesar’s landing in Kent, waiting instead until he began to move inland. Caesar’s forces eventually made their way into Middlesex and crossed the Thames, forcing the British warlord Cassivellaunus to surrender, after which Caesar set up Mandubracius of the Trinovantes as client king, basically a sub king. As with all conquerors, Caesar included the accounts of both invasions in his Commentarii de Bello Gallico, with the first significant first-hand description of the people, culture, and geography of the island. Caesar’s writings are thought to be the start of the written history or at least the protohistory of Britain.
It seems odd to me to think that people could simply not think that Britain exists, but I suppose that in a huge part of our world’s history, and actually still with some people today, it was thought that the Earth is flat, meaning that the horizon we see is all there is. If that is your mindset, it would be easy to limit the Earth to the horizon we can see, but it would not be an assumption that would be based on fact. Now with satellites and airplanes we know that the Earth is definitely round, just like the Bible and most people have said. And that said, we know that Britain existed long before the men of Caesar’s time found and invaded.