Brennus' army is the common name for the Senone force that sacked Rome and Veii. It was one of the most successful armies of all time, taking down Rome, and successfully defeating the Umbrians. In addition, it serves as the model for almost all successful future Senone armies, and inspired the contemporary composition of the Senone Republics army. In addition to influencing Senone military culture, the army has appeared in almost every major military textbook, and many successful generals have taken tactical influence from Brennus and his army. Overall, Brennus' army has had great affect on military history, and has influenced many other aspects of politics and conflict.
Brennus' army was first made up of three kinds of troops, light soldiers, heavy soldiers, and spearmen. About 20% of the army were spearmen, while 30% was heavy soldiers and the remaining 50% light soldier. The load out of the light soldier was a short sword, a round shield, and a spear. Their armor was primarily light, and in some cases nonexistent, and as a result, most of the casualties were light soldiers. The load out for the heavy soldier was a two swords, a short one and a long one, as well as a large rectangular shield and heavy armor. The Spearman's load out was a short sword and two throwing spears. Armor was light, but casualties were low for the spearmen, as they generally remained remained on the edges of the battle field.
The primary tactic used by Brennus' army was relatively simple, but extremely effective. The heavy soldiers would be put in the middle, while the light soldiers advanced on the side. The spearmen would either by in the back of the formation, or over to one side. This would usually destroy the opposing army, and using this strategy, the army never lost a battle. Other effective forms included putting the light troops in the middle with the heavy soldiers on the side. This was not used as often, but was useful several times against and enemy force attacking from the sides. In addition to these tactics, Brennus' army also employed many tactics on a smaller scale, many of them effective and still used to this day.