Bulfinch's Mythology

About this time it happened (as is found in the Roman histories) that Julius Caesar, having subdued Gaul, came to the shore opposite Britain. And having resolved to add this island also to his conquests, he prepared ships and transported his army across the sea, to the mouth of the River Thames. Here he was met by Cassibellaun with all his forces, and a battle ensued, in which Nennius, the brother of Cassibellaun, engaged in single combat with Csesar. After several furious blows given and received, the sword of Caesar stuck so fast in the shield of Nennius that it could not be pulled out, and the combatants being separated by the intervention of the troops Nennius remained possessed of this trophy. At last, after the greater part of the day was spent, the Britons poured in so fast that Caesar was forced to retire to his camp and fleet. And finding it useless to continue the war any longer at that time, he returned to Gaul.