For over 400 years the Romans governed Britain, and they brought with them their culture, architecture, religion, language and military. The Roman army first arrived under Julius Cesar in 55/54 BC. The first invasion was unsuccessful, leading to a 2nd attempt the following year.
Cesar defeated Cassivelanus in the area which is known as Hertfordshire, on this occasion the Romans didn’t stay, trade contracts were increased, but there would be no permanent Roman presence until the invasion by Claudius in AD 43.
Then from AD 43 Britain would be known as Britannia, and would become a Roman Province for over 400 years. The legions quickly established themselves in South England, and very quickly colonies were established at Colchester and Lincoln further north. Road networks were built allowing troops to move quickly across the country.
It took 30 years to conquer and quell the tribes in Britain, with only one major setback in AD 60 when Boudicca and the Iceni revolted. They sacked Londinum and ran amok, before being destroyed on the field of battle.
Agricola led the first incursions into Scotland in AD 80, which resulted in the defeat of the Caledonians in AD 84. By 87 AD the highlands of Scotland were abandoned, by 105 AD the Roman army abandoned the Scottish lowlands as well. A new frontier was established along the Stanegate (Tyne-Solway line).
Then in AD 120 Hadrian visited the Island, and establishes a permanent frontier between the Solway and the Tyne. This is known today as Hadrian’s Wall, running over 80 km, it stood as a symbol of Roman power for centuries. It was also an important military zone in Britain and Europe, due to the country becoming a major producer of grain for the empire.