What does the Latin phrase "divide et impera" mean?

Divide and rule (Latin: divide et impera), or divide and conquer, in politics and sociology is gaining and maintaining power by breaking up larger concentrations of power into pieces that individually have less power than the one implementing the strategy.

The use of this technique is meant to empower the sovereign to control subjects, populations, or factions of different interests, who collectively might be able to oppose his rule. Niccolò Machiavelli identifies a similar application to military strategy, advising in Book VI of The Art of War (1521) (L'arte della guerra): a Captain should endeavor with every art to divide the forces of the enemy. Machiavelli advises that this act should be achieved either by making him suspicious of his men in whom he trusted, or by giving him cause that he has to separate his forces, and, because of this, become weaker.

The maxim divide et impera has been attributed to Philip II of Macedon. It was utilised by the Roman ruler Julius Caesar and the French emperor Napoleon (together with the maxim divide ut regnes).