When rome conquered a new terrirory, what was their policy of setting a new law on the recently aquired land?
I mean: the legion could not just stay on a place indefinitely (too many mouths to feed, also the need of conquering further)
Leaving a small detachment behind could work, but eventually you should start training new local chieftains (after their ancestors had been murdered or subdued) into rome's laws.
How has it been handled by other empires?
Today is very easy to have a globalized world order and laws with our media and communication networks, but how did you keep a world order back then, as faithfully possible to the source?
>>3238436
Generally, they didn't set up new law. They installed puppet local leaders and demanded taxes and occasional manpower tithes. If the cash and other resources were provided, they were generally more or less allowed to run their own domestic affairs.
>>3238450
This. The romans tended to not outright conquer a region but rather establish client states which they would then annex when the population had been sufficiently romanized. Ofc, this wasn't the case all the time and they did also conquer territories. They often, if I'm not mistaken, set up colonies in these newly aquired territories which were comprised of, amongst other people, retired legionaries.