"warfare" is "warfare"; but as to the latter, the rules they do change - as to strategy (probably the least), tactics and "war crimes".

For example, one of our favorite generals (Subotai) employed the "wagon wheel test" to separate the "goats" from the "sheep" - too tall and your head was removed to put you in the eternal "sheep class". His problem (in occupying adverse territory) was that he had too few troops to "clear and hold" (much less "build"). So, all potential insurgents had to be removed.

What was "acceptable" to that non-Mongol would scarcely be "acceptable" today; but what is "acceptable" today has many variants (compare EU vs US and have fun). "Old Law" is not necessarily bad - especially where it had clarity.

Regards

Mike