In AD59 the Roman governor, Suetonius Paulinus, was in Wales, launching an attack against the Druids who were based on the island of Anglesey and who were suspected as being a major source of opposition to Roman rule.
At the same time, Prasutagus, king of the Iceni, a tribe in East Anglia, died. There seems to have been some special relationship and alliance with Rome, perhaps in return for services rendered by Prasutagus at the time of the invasion in AD43 when the Romans had not conquered the powerful Iceni tribe but made a pact with their king. This arrangement, which enabled the Romans to concentrate their army elsewhere, was tactically astute but strategically hazardous.
When Prasutagus died, the Iceni assumed that the king’s status as client ruler would pass automatically to his wife, Queen Boudica. The Romans, however, saw client status as a convenient temporary arrangement which could be terminated at will.