system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:In ancient and medieval times, how did soldiers distinguish friend from foe in battle?

When I look at movies that have vikings etc in them, they have no regulation uniforms whatsoever and their enemies wear roughly the same looking gear. How did the soldiers know, who were the enemies?
gpt
Sometimes they didn't. However for the most part it involved big flags and designs on the shields. Some armies were equipped totally different but others where similarly equipped there were special people called heralds who could tell whose design on a flag or shield were who and which side they were supposed to be on.