Hi u/BingBongTheArtcher, thanks for the question.

I'm afraid I can't answer the entire question but I did go into detail on concentration camps as perpetrated by the British in South Africa during the Second Anglo-Boer War (1899-1901) through the perspective of Emily Hobhouse as part of this previous answer which should give you some perspective.

But just to briefly answer:

Concentration Camps as we understand them now are fairly modern, having roots at the turn of the century. Though, arguably the first 'modern' concentration camps occurred in the early 1800's in the US during their campaigns to claim land and wipe out the Native American populations.

And this is what we need to bear in mind when defining concentration camps, as they are typically socio-political in nature and serve the purpose of targeting a specific population for some gain.

For example, the Native American camps were created in order to force the populations to capitulate and leave their lands for 'settlers', but had the added 'benefit' of forcing the population to wither and die, thus killing resistance along with it.

The same happened during the Anglo-Boer War wherein women, children, and the elderly were forced into camps to force the Boer guerrilla fighters (their husbands, brothers, sons, fathers etc) to lay down arms. It 'just so happened' that by doing so it weakened the Boer population as well and allowed for an easier occupation by the British.

Similarly, the Nazi concentration camps were formed to segregate and eventually exterminate populations deemed threatening to the greater functioning and health of German society. And Japanese internment camps in the US were also to segregate a potentially 'dangerous' population from taking sides against their own countrymen during WWII.

However, the question is, did such camps exist in antiquity? It is hard to say as it depends on how we define these camps and the actions surrounding them.

The modern concentration camp has a very particular design which requires social mobility, political will, firearms, and modern communication technologies (printing, telegraph, propaganda, radio) to function. These technologies allowed for large groups of people to be corralled and controlled by far fewer people and more efficiently. The concept of the Nation State is also a primary factor as it established borders, boundaries, and large-scale identity which helps prevent target populations (the 'other') from fleeing too far, whilst ensuring those establishing and supporting the camps have a socio-political boundary, as well as a physical border, in which to operate with impunity.

I have no doubt that in wars throughout history populations were corralled and subjected to genocidal treatments for all the reasons outlined above - human society hasn't changed that much I'm afraid. However, the ABILITY to inter people in the WAY that concentration camps do is fairly modern and required modern technologies and society to establish.

In the past, if populations were targeted for genocidal actions it was likely done swiftly and as part of an already established campaign. Capturing the population, placing them in large-scale housing, establishing resource lines to keep them alive for as long as needed, and ensuring your own civilian population was also allowing this to happen through carefully controlled propaganda campaigns, was just not feasible. Rather, these targeted populations would probably have simply been driven out or exterminated where they were found.

Note: this is different to prisoners captured during war, or slave populations, as slaves functioned as a workforce and prisoners were often either killed, traded, enslaved, or sold in antiquity. Even if they were briefly interred, the goal was to keep them alive for profit, or to kill to prevent immediate or eventual revolt, not to exterminate a specific population over a period of time in an established facility specifically for that point.

There is a LOT more to be said and hopefully another member will help provide you with those, but I hope this will at least serve as a primer for you.

Good luck!