Aeneas Tacticus 15.8-10: Severe losses incurred by overenthusiastic troops.

8. A raid made by the Triballi into the country of Abdera was met in a splendid fashion by the men of Abdera, who marched out and were victorious in a pitched battle against this powerful and warlike tribe, inflicting great loss on them. 9. The Triballi, mortified by their defeat, retired to collect their forces, and then advanced a second time, posting an ambush as they went, and proceeded to lay waste to the territory of Abdera within a short distance of the city. The men of Abdera, whose previous success had made them despise their enemy, rushed out and charged them with the utmost vigour and enthusiasm; the enemy led them on, step by step into the ambush; 10. and therefore they lost more men, it is said, than any other city of the same size ever lost in so short a space of time. For even when news reached the city of the fate of the first sally, men kept pouring out, cheering one another on in their eagerness to rescue those who were in front, until not a man was left within the walls.