Since I started to interest myself in history of the northen Europe, and especially the history of Celtic people, I read a lot about their inventions, in terms of warfare.
The quote from wiki
The use of mail as battlefield armour was common during the Iron Age and the Middle Ages, becoming less common over the course of the 16th and 17th centuries. It is believed that the Roman Republic first came into contact with mail fighting the Gauls in Cisalpine Gaul, now Northern Italy, but a different pattern of mail was already in use among the Etruscans. The Roman army adopted the technology for their troops in the form of the lorica hamata which was used as a primary form of armour through the Imperial period.
I really started to doubt that, because armor of course is a huge advantage. But yet, most of the encounters of the Celts with the Romans were a defeat to the Celtic side.
Is there any actual source or finding to support that Celtic tribes have produced mail armour? Is there for example any evidence, that the Brennus of Senones and his troops used mail, when they attacked the early Roman Republic?