Indutiomarus was a Treviri nobleman who played a major role in the second Gallic revolt against Julius Caesar. He is first mentioned just before the start of Caesar's second expedition to Britain in 54 BC. The Treviri, whose lands bordered on the Rhine, had not attended Caesar's general diets of Gaul, and it was now suspected that they were attempting to gather allies in Germany. Caesar led four legions and 800 cavalry on a quick raid into Treviri territory to make sure that a revolt wouldn't break out while he was in Britain.
Caesar discovered that two noblemen – Indutiomarus and Cingetorix – were involved in a power struggle. As the Romans approached Cingetorix came to meet Caesar, and promised to stay loyal, but Indutiomarus began to raise an army and prepared to fight. He soon discovered that he had very little support amongst the tribe's nobles, as most of them paid court to Caesar. Indutiomarus was forced to abandon his plans, and sent a message to Caesar in which he claimed that he had stayed at home to make sure that the common people didn't revolt while all the nobles away. For the moment Caesar pretended to believe this story. Indutiomarus was pardoned for his actions but had to surrender 200 hostages, including his son, while Caesar made it clear that he preferred Cingetorix.
While Caesar was in Britain Indutiomarus clearly continued to prepare for a rebellion, sending letters to nearby rulers. On their return to Gaul the Romans went into unusually widely scattered winter quarters. Fifteen days later the revolt broke out. Ambiorix and Cativolcus, the co-rulers of the Eburones, attacked the camp at Atuatuca, where they destroyed a legion and a half under the command of Sabinus. Ambiorix then moved on to attack the camp of Q. Cicero, while Indutiomarus prepared to attack Labienus's camp. This attack never took place. Caesar gathered a small relief force and lifted the siege of Cicero's camp. When he received this news Indutiomarus retreated back into Treviri territory.
Indutiomarus spent the first part of the winter in an unsuccessful attempt to get German aid. When this failed he called an armed council, which was attended by a number of rebellious tribes. At the council Indutiomarus declared Cingetorix to be an enemy of the tribe and confiscated his property. He then announced that he was going to march into Remi territory to attack Labienus in his winter quarters.
Hardly surprisingly Cingetorix and his allies quickly made their way to Labienus's camp and informed him of Indutiomarus's plans. Labienus realised that he had a chance to eliminate one of the most dangerous Gallic leaders. He gathered a strong force of Gallic cavalry and concealed them in his camp. When Indutiomarus arrived outside the Roman camp Labienus refused to allow his men to leave their camps. After a few days of this the Gauls believed that they were safe. This was what Labienus had been waiting for. At the end of another day outside the Roman camp Indutiomarus and his men set off on the journey back to their camp without taking any precautions against an attack. Labienus unleashed his cavalry, with orders to focus their efforts on catching Indutiomarus. Caught by surprise the rebels were unable to defend their leader and Indutiomarus was killed at a ford across a nearby river.