There is an eternal paradox in human sentiments between innate compassion on the one hand and utter cruelty on the other, with indifference in the middle.  While in peacetime, utter cruelty is rarely practised in inter-human relations, in wartime, there is ample scope for it.  Greek and Roman historiography records many instances of it.  There are also records of instances when rulers or military commanders showed compassion, but these were, it seems, exceptional, and because of this made it into the history books.  Even once Christianity had “invented” the notion that one must be compassionate even towards slaves (leading eventually to the abolition of slavery among Christians in the high middle ages), it took centuries to impress upon Christians hosts that they must not maltreat their own peasant populations (mainly to secure victuals and farm animals).  Arguably, it was only from the 15th century that military commanders extended that injunction to the treatment of enemy civilians.  These were of little effect in the Thirty Years’ War, but from then onwards there were some signs of institutionalised compassion with civilian populations and even enemy prisoners of war.  The situation was reversed with the rise of nationalism and racism: these ideologies from the late 19th century pitted nations against each other in a Darwinist fight for the survival of the fittest, with mass armies, mass casualties, a mass destruction of civilian property marking the First, and deliberate attacks on civilian populations the Second World War.  Efforts made in recent decades to protect civilian populations from the ravages of war recall practices of the 18th century, and yet are half-hearted even now.