In AD 60 or 61, while the current governor, Gaius Suetonius Paulinus, was leading a campaign against the island of Mona (modern Anglesey) in the north of Wales, which was a refuge for British rebels and a stronghold of the druids, the Iceni conspired with their neighbours the Trinovantes, amongst others, to revolt.
Boudica was chosen as their leader.
Tacitus records that she addressed her army with these words, "It is not as a woman descended from noble ancestry, but as one of the people that I am avenging lost freedom, my scourged body, the outraged chastity of my daughters," and concluded, "This is a woman's resolve; as for men, they may live and be slaves."
According to Tacitus, they drew inspiration from the example of Arminius, the prince of the Cherusci who had driven the Romans out of Germany in AD 9, and their own ancestors who had driven Julius Caesar from Britain.
Dio says that at the outset Boudica employed a form of divination, releasing a hare from the folds of her dress and interpreting the direction in which it ran, and invoked Andraste, a British goddess of victory.

The rebels' first target was Camulodunum (modern Colchester), the former Trinovantian capital and, at that time, a Roman colonia.
The Roman veterans who had been settled there had mistreated the locals, and a temple to the former emperor Claudius had been erected there at local expense, making the city a focus for resentment.
The Roman inhabitants sought reinforcements from the procurator, Catus Decianus, but he sent only two hundred auxiliary troops.
Boudica's army fell on the poorly defended city and destroyed it, besieging the last defenders in the temple for two days before it fell.
A bronze statue to the emperor Nero, which probably stood in front of the temple, was decapitated and its head taken as a trophy by Boudica's army Archaeologists have shown that the city was methodically demolished.
The future governor Quintus Petillius Cerialis, then commanding the Legio IX Hispana, attempted to relieve the city, but suffered an overwhelming defeat.
The infantry with him were all killed – only the commander and some of his cavalry escaped. "
The victorious enemy met Petilius Cerialis, commander of the ninth legion, as he was coming to the rescue, routed his troops, and destroyed all his infantry.
Cerialis escaped with some cavalry into the camp, and was saved by its fortifications."
 The location of this battle is unknown, but has been claimed by some modern localities.
After this defeat, Catus Decianus fled to Gaul.

When news of the rebellion reached Suetonius, he hurried along Watling Street through hostile territory to Londinium.
Londinium was a relatively new settlement, founded after the conquest of AD 43, but it had grown to be a thriving commercial centre with a population of traders, and, probably, Roman officials.
Suetonius considered giving battle there, but considering his lack of numbers and chastened by Petillius's defeat, decided to sacrifice the city to save the province.

Alarmed by this disaster and by the fury of the province which he had goaded into war by his rapacity, the procurator Catus crossed over into Gaul.
Suetonius, however, with wonderful resolution, marched amidst a hostile population to Londinium, which, though undistinguished by the name of a colony, was much frequented by a number of merchants and trading vessels.
Uncertain whether he should choose it as a seat of war, as he looked round on his scanty force of soldiers, and remembered with what a serious warning the rashness of Petillius had been punished, he resolved to save the province at the cost of a single town.
Nor did the tears and weeping of the people, as they implored his aid, deter him from giving the signal of departure and receiving into his army all who would go with him.
Those who were chained to the spot by the weakness of their sex, or the infirmity of age, or the attractions of the place, were cut off by the enemy.—
Tacitus
Londinium was abandoned to the rebels, who burnt it down, torturing and killing anyone who had not evacuated with Suetoniu
In AD 60 or 61, while the current governor, Gaius Suetonius Paulinus, was leading a campaign against the island of Mona (modern Anglesey) in the north of Wales, which was a refuge for British rebels and a stronghold of the druids, the Iceni conspired with their neighbours the Trinovantes, amongst others, to revolt. Boudica was chosen as their leader. Tacitus records that she addressed her army with these words, "It is not as a woman descended from noble ancestry, but as one of the people that I am avenging lost freedom, my scourged body, the outraged chastity of my daughters," and concluded, "This is a woman's resolve; as for men, they may live and be slaves." According to Tacitus, they drew inspiration from the example of Arminius, the prince of the Cherusci who had driven the Romans out of Germany in AD 9, and their own ancestors who had driven Julius Caesar from Britain. Dio says that at the outset Boudica employed a form of divination, releasing a hare from the folds of her dress and interpreting the direction in which it ran, and invoked Andraste, a British goddess of victory.
The rebels' first target was Camulodunum (modern Colchester), the former Trinovantian capital and, at that time, a Roman colonia. The Roman veterans who had been settled there had mistreated the locals, and a temple to the former emperor Claudius had been erected there at local expense, making the city a focus for resentment. The Roman inhabitants sought reinforcements from the procurator, Catus Decianus, but he sent only two hundred auxiliary troops. Boudica's army fell on the poorly defended city and destroyed it, besieging the last defenders in the temple for two days before it fell. A bronze statue to the emperor Nero, which probably stood in front of the temple, was decapitated and its head taken as a trophy by Boudica's army Archaeologists have shown that the city was methodically demolished. The future governor Quintus Petillius Cerialis, then commanding the Legio IX Hispana, attempted to relieve the city, but suffered an overwhelming defeat. The infantry with him were all killed – only the commander and some of his cavalry escaped. "The victorious enemy met Petilius Cerialis, commander of the ninth legion, as he was coming to the rescue, routed his troops, and destroyed all his infantry. Cerialis escaped with some cavalry into the camp, and was saved by its fortifications."  The location of this battle is unknown, but has been claimed by some modern localities. After this defeat, Catus Decianus fled to Gaul.
When news of the rebellion reached Suetonius, he hurried along Watling Street through hostile territory to Londinium. Londinium was a relatively new settlement, founded after the conquest of AD 43, but it had grown to be a thriving commercial centre with a population of traders, and, probably, Roman officials. Suetonius considered giving battle there, but considering his lack of numbers and chastened by Petillius's defeat, decided to sacrifice the city to save the province.
Alarmed by this disaster and by the fury of the province which he had goaded into war by his rapacity, the procurator Catus crossed over into Gaul. Suetonius, however, with wonderful resolution, marched amidst a hostile population to Londinium, which, though undistinguished by the name of a colony, was much frequented by a number of merchants and trading vessels. Uncertain whether he should choose it as a seat of war, as he looked round on his scanty force of soldiers, and remembered with what a serious warning the rashness of Petillius had been punished, he resolved to save the province at the cost of a single town. Nor did the tears and weeping of the people, as they implored his aid, deter him from giving the signal of departure and receiving into his army all who would go with him. Those who were chained to the spot by the weakness of their sex, or the infirmity of age, or the attractions of the place, were cut off by the enemy.— Tacitus
Londinium was abandoned to the rebels, who burnt it down, torturing and killing anyone who had not evacuated with Suetoniu
Boudica