The Romans were prone to talk about Divide and Conquer because they were effective politicians. Manipulating people was the name of the game. Know your enemy is part of it. Know what they want. Offer what they want. Let them fight for short term advantage then pick up the pieces.
The Romans did it. Machiavelli explained it. Cesare Borgia did it; his treachery was legendary. Machiavelli wrote about evil, Borgia's evil thus founding the subject of Political Science.
Now, in the Third Millennium he has his followers. Our Invisible Enemy, the Puppet Masters use Divide and Conquer; it is a working tool; one summarised by Hegel, a dismal rogue as "thesis, antithesis, synthesis". Hegel influenced Adolf Hitler as well as Karl Marx.