The Romans conquered Britain over the course of one hundred and fifty years. Julius Caesar was the first to attempt it. He established a beachhead in the east, but never got further into the country despite multiple expeditions.
“His first expedition, however, was ill-conceived and too hastily organised. With just two legions, he failed to do much more than force his way ashore at Deal and win a token victory that impressed the senate in Rome more than it did the tribesmen of Britain. In 54 BC, he tried again, this time with five legions, and succeeded in re-establishing Commius on the Atrebatic throne. Yet he returned to Gaul disgruntled and empty-handed, complaining in a letter to Cicero that there was no silver or booty to be found in Britain after all.” http://www.bbc.co.uk/history/ancient/romans/questions_01.shtml
100 years later, in 43 AD, the Emperor Claudius determined to try again, and this time the Romans would not be dissuaded. By 60 AD, after many years of upheaval, factional disputes and multiple emperors and governors, C. Suetonius Paullinus was chosen to lead the forces in Wales and put down the Druids on Anglesey.
“This island had become the last point of retreat for the rebels. Being surrounded by water, this was logical since the British forces could only retreat towards the sea. The Druids, seen as one of the strongest band of people in Britain, were also on the island. Angelsey was to be no pushover. It is written that it was defended by praying Druids, fierce warriors and wild women. The assault and taking of Angelsey was brutal, bloody and savage in the extreme.” http://www.allempires.com/article/index.php?q=conquest_roman_britain
After the defeat of Anglesey and the destruction of the druids, Boudicca rose in rebellion. The Roman legions were busy cleaning up the mess they had made there, so had left little protection in the east.
“Boudicca was married to Prasutagus, ruler of the Iceni people of East Anglia. When the Romans conquered southern England in AD 43, they allowed Prasutagus to continue to rule. However, when Prasutagus died the Romans decided to rule the Iceni directly and confiscated the property of the leading tribesmen. They are also said to have stripped and flogged Boudicca and raped her daughters. These actions exacerbated widespread resentment at Roman rule.
Boudicca’s warriors successfully defeated the Roman Ninth Legion and destroyed the capital of Roman Britain, then at Colchester. They went on to destroy London and Verulamium (St Albans). Thousands were killed. Finally, Boudicca was defeated by a Roman army led by Paulinus. Many Britons were killed and Boudicca is thought to have poisoned herself to avoid capture. The site of the battle, and of Boudicca’s death, are unknown.” http://www.bbc.co.uk/history/historic_figures/boudicca.shtml
“The main Roman army was making its way back from Angelsey along the Watling Road. Suetonius knew he was heavily outnumbered, so he selected a place for the battle and waited for the Iceni to come to him. With dense woodland protecting his rear and a narrow defile in front, he was in a position where his troops (outnumbered by 10 to 1) had the advantage.
The Iceni, so confident of victory, charged down the defile falling over each other in the charge. The Romans stood firm. The Iceni charged again and again, but they were no match for the diciplined Romans, and in the end the Romans charged against the Iceni trapping them against the waggons that had followed the army. By the end of the day 80,000 Iceni lay dead.” http://www.oldcity.org.uk/norwich/names/boudicca.php
The timeline for these events is here: http://www.historyonthenet.com/Chronology/timelineroman.htm
The ordnance survey has some excellent maps that are less accessible than they were (but I bought so as to have a paper copy). You can see the roman roads and all the ruins in Wales through Getamap: http://www.getamap.ordnancesurveyleisure.co.uk/
I use this all the time, not only for Roman ruins, but for all ancient artifacts on the landscape.