The Iceni were a Celtic tribe which existed in Norfolk before and during the occupation of Britain by the Roman Empire in 43. Its capital was Venta Icenorum while the tribe had a population of approximately 900 in 60.
Following the Roman conquest, its king Prasutagus was one of several tribal rulers in Britain who were bought off by the Romans. After Prasutagus' death, he left half of his kingdom to the Roman Emperor Nero and the other half to his daughters. His widow Boudica became the Queen of the Iceni. However, the Emperor annexed the entire kingdom. When Boudica objected, she was flogged while her daughters were raped in public. This led to Boudica's revolt against the occupying Roman forces in 60. In their efforts, the Iceni were supported by the Trinovantes and Brigantes.
The Fourth Doctor and his companion Leela encountered Boudica in 60, in the midst of the Iceni-led revolt. In order to prevent Boudica from severing the Doctor's head, Leela told her that the Doctor was a prophet who foresaw her defeat at the hands of the Romans. The Doctor told her that the forces at the Roman capital Camulodunum were a decoy and Roman governor Suetonius Paulinus had stationed an army to the north and intended to attack Boudica's army while it was ransacking Camulodunum. However, this was not the case. There was no army to the north.
After the burning of Camolundunum, the Iceni and their allies marched to Londinium and slaughtered almost everyone in the city including the old, the weak and the infirm. Boudica was eventually defeated in a field in the middle of England which no has ever been able to identify. Her army may have numbered up to 80,000 by this time but the Doctor notes that this figure could have been exaggerated by later historians. There were no survivors. Instead of allowing the Romans to execute her, Boudica killed her daughters before killing herself. The Doctor told Leela that he had no desire to to witness Boudica's defeat first hand. (AUDIO: The Wrath of the Iceni)