公元43年，罗马建城纪元796年，罗马帝国第四位元首Claudius即位后的第3年（含即位年本身）。
这一年，罗马帝国终于征服了此前一直没能征服的不列颠地区，罗马帝国的“元首直辖行省”列表之中，又多了一个新的行省——Britannia。

根据后来英国人自己写的那些有点荒诞，但依然能清晰看出这次入侵的那些史料，这次入侵大致如下：
“The second after him, who came into Britain, was the emperor Claudius, who reigned forty-seven years after the birth of Christ（注：不同版本的基督纪年造成的误差。这里的版本与我们常用的Common Era相差4年，正好是希律王之死到公元1年之间的差异。）. He carried with him war and devastation; and, though not without loss of men, he at length conquered Britain. He next sailed to the Orkneys, which likewise conquered, and afterwards rendered tributary. No tribute was in his time received from the Britons; but it was paid to British emperors. He reigned thirteen years and eight months.（History of Britons）”
“KYMBELINUS, when he had governed Britain ten years, begat two sons, the elder named Guiderius, the other Arviragus. After his death the government fell to Guiderius. This prince refused to pay tribute to the Romans; for which reason Claudius, who was now emperor, marched against him. He was attended in this expedition by the commander of his army, who was called in the British tongue, Leuis Hamo, by whose advice the following war was to be carried on. This man, therefore, arriving at the city of Portcestre, began to block up the gates with a wall, and denied the citizens all liberty of passing out. For his design was either to reduce them to subjection by famine, or kill them without mercy.
GUIDERIUS, upon the news of Claudius's coming, assembled all the soldiery of the kingdom, and went to meet the Roman army. In the battle that ensued, he began the assault with great eagerness, and did more execution with his own sword than the greater part of his army. Claudius was now on the point of retreating to his ships, and the Romans very nearly routed, when the crafty Hamo, throwing aside his own armour, put on that of the Britons, and as a Briton fought against his own men. Then he exhorted the Britons to a vigourous assault, promising them a speedy victory. For he had learned their language and manners, having been educated among the British hostages at Rome. By these means he approached by little and little to the king, and seizing a favourable opportunity, stabbed him while under no apprehension of danger, and then escaped through the enemy's ranks to return to his men with the news of his detestable exploit. But Arviragus, his brother, seeing him killed, forthwith put on his brother's habiliments, and, as if he had been Guiderius himself, encouraged the Britons to stand their ground. Accordingly, as they knew nothing of the king's disaster they made a vigorous resistance, fought courageously, and killed no small number of the enemy. At last the Romans gave ground, and dividing themselves into two bodies, basely quitted the field. Caesar with one part, to secure himself, retired to his ships; but Hamo fled to the woods, because he had not time to get to his ships. Arviragus, therefore, thinking that Claudius fled along with him, pursued him with all speed, and did not leave off harassing him from place to place, till he overtook him on a part of the sea-coast, which, from the name of Hamo, is now called Southampton. There was at the same place a convenient haven for ships, and some merchant ships at anchor. And just as Hamo was attempting to get on board them Arviragus came upon him unawares, and forthwith killed him. And ever since that time the haven has been called Hamo's port.（不列颠诸王史）”

而Suetonius的《罗马十二帝王传》则是这样写的：
“Claudius only fought one campaign, which was of small importance. The Senate had voted him triumphal regalia, but he thought accepting them beneath his dignity, and sought the glory of a legitimate triumph. He decided Britain was the optimum place for gaining one, as no one had attempted a conquest since Caesar’s ventures (55/54BC), and the place was in a state of rebellion because the Romans had refused to return certain deserters.
He sailed from Ostia and was nearly shipwrecked by north-westerly gales, firstly off Liguria and then near the Stoechades Islands (Hyéres Islands). Landing at Massilia (Marseilles), therefore, he travelled cross-country to Gesoriacum (Boulogne), crossed the Channel from there, and received the submission of part of the island in very few days without battle or bloodshed (AD43). He was back in Rome within six months, and there celebrated a splendid triumph. He summoned the provincial governors to Rome to witness the spectacle, and even certain exiles. To mark his success, he set one of the victory tokens, the naval crown, on a gable of the Palace next to the civic crown, signifying that he had crossed and conquered, so to speak, the Ocean. ”
无论如何记载，虽然对于已经覆盖了整个地中海的罗马帝国来说，这次征服并不是十分重要（不像前30年灭埃及确立了Octavianus的势力在地中海的权威，或是像布匿战争彻底改变了罗马历史的发展轨迹，除了奴隶市场又多了一批奴隶之外，征服不列颠对于地中海沿岸的其他人没什么大的影响。），这次征服在不列颠史上都是一件意义重大的事件。从此，不列颠的凯尔特人失去了独立和自由，直到5世纪日耳曼人大入侵，罗马帝国在西欧的统治彻底垮台为止。

1楼地图不见了

罗马帝国的不列颠尼亚行省应该是公元43年建立的吧，第一任总督是奥鲁斯·普劳提乌斯