From Wikipedia

Great Druid Massacre

After capturing the south of the island, the Romans turned their attention to what is now Wales. The Silures, Ordovices and Deceangli remained implacably opposed to the invaders and for the first few decades were the focus of Roman military attention, despite occasional minor revolts among Roman allies like the Brigantes and the Iceni. The Silures were led by Caratacus, and he carried out an effective guerilla campaign against Governor Publius Ostorius Scapula. Finally, in 51 AD, Ostorius lured Caratacus into a set-piece battle and defeated him. The British leader sought refuge among the Brigantes, but their queen, Cartimandua, proved her loyalty by surrendering him to the Romans. He was brought as a captive to Rome, where a dignified speech he made during Claudius's triumph persuaded the emperor to spare his life. However, the Silures were still not pacified, and Cartimandua's ex-husband Venutius replaced Caratacus as the most prominent leader of British resistance.

In 60-61 AD, while Governor Gaius Suetonius Paulinus was campaigning in Wales, the southeast of Britain rose in revolt under the leadership of Boudica. Boudica was the widow of the recently-deceased king of the Iceni, Prasutagus. The Roman historian Tacitus reports that Prasutagus had left a will leaving half his kingdom to Nero in the hope that the remainder would be left untouched. He was wrong. When his will was enforced, Rome responded by violently seizing the tribe's lands in full. Boudica protested. In consequence, Rome punished her and her daughters by flogging and rape. In response, the Iceni, joined by the Trinovantes, destroyed the Roman colony at Camulodunum (Colchester) and routed the part of the IXth legion that was sent to relieve it. Suetonius Paulinus rode to London, the rebels' next target, but concluded it could not be defended. Abandoned, it was destroyed, as was Verulamium (St Albans). Between seventy and eighty thousand people are said to have been killed in the three cities. But Suetonius regrouped with two of the three legions still available to him, chose a battlefield, and, despite being heavily outnumbered, defeated the rebels in the Battle of Watling Street. Boudica died not long afterwards, by self-administered poison or by illness. During this time, the Emperor Nero considered withdrawing Roman forces from Britain altogether.