Humanity also has a pretty extensive history of conflict, even in more mono-cultural societies.  Hell, you could take any mass of people, all from the same background, race, ethnicity, religion, etc (take your pick), put them on an island for a hundred years or two, and you&#x27;ll get factions.<p>You&#x27;ll get people fighting over how they think the place ought to be run.  You&#x27;ll get people fighting over who gets what and why these guys have all this stuff and we have less stuff.  If nothing else, it comes down to availability of resources and numbers of people (along the lines of Dunbar&#x27;s number and all that).<p>Sure, ethnicity, race, and religion are convenient signifiers of groups of people and usually when you have two or more groups with significantly different cultures, you&#x27;ve probably got two or more groups with some level of inequality and power imbalance so you&#x27;re already halfway there.  But even if you don&#x27;t start out with cultural differences, they&#x27;ll pop up eventually.  Groups of people over a certain size will always have a harder time avoiding conflict when things get tough.  It&#x27;s almost in our nature to split into &quot;us&quot; and &quot;them&quot; just to manage it all.