The following year Caesar prepared for a new expedition and assembled a much larger force to take part in it, which included five Roman legions, 2,000 Gallic horsemen and more than 600 ships.In July 54 B.C., with these forces, he landed again on the island. The Britons also prepared for the invasion, having concluded a military alliance among themselves and placing Cassivelaun at the head of all the combined forces.
After a series of initial successes, the Britons attacked the larger Roman force, but suffered heavy losses and were forced to retreat beyond the Thames. While pursuing them, the Romans also crossed the Thames and ravaged the territory belonging to Cassivelaunus himself. The local chiefs then sent their representatives to Caesar to ask for peace. Cassivelaunus' attempt to get his allies to attack Caesar's camp was unsuccessful. Having learnt of the ruin of his lands, of defeat and betrayal, he found it best to negotiate. Caesar demanded from him the release of hostages, set the amount of tribute.
After a series of initial successes, the Britons attacked the larger Roman force, but suffered heavy losses and were forced to retreat beyond the Thames. While pursuing them, the Romans also crossed the Thames and ravaged the territory belonging to Cassivelaunus himself. The local chiefs then sent their representatives to Caesar to ask for peace. Cassivelaunus' attempt to get his allies to attack Caesar's camp was unsuccessful. Having learnt of the ruin of his lands, of defeat and betrayal, he found it best to negotiate. Caesar demanded from him the release of hostages, set the amount of tribute.