Armor: How effective was Chainmail

[Dan Howard]

I may be imagining things, but I though I read somewhere that seg. became popular with Caesar's troops because of the number of debilitating wounds they were receiving to their shoulders and collar bones in Gaul due to overhead blows from longswords and projectiles during sieges.

It is likely that Caesar died before segmentata was invented so it would have been pretty hard for his troops to use it in Gaul. In any case, mail was perfectly capable of protecting the shoulders from anything that the Romans faced in Gaul or later in Dacia - especially the Greek-style hamata with the shoulder doublings.