Reference for "divide et impera"

Question

The motto "divide et impera" is often attributed to Caesar (I don't want to spam here some low quality references, simply made a Google search). Wikipedia says that

The maxim divide et impera has been attributed to Philip II of Macedon [clearly not in the latin form]. It was utilised by the Roman ruler Julius Caesar and the French emperor Napoleon...

but no reference is made to support this hypothesis (actually, the italian encyclopaedia Treccani is a reference for the claim about Philip II, but there is no further information about who made this claim first).

There does not seem to be any direct quotation in Caesar's works, but there may be an attribution made by another author.

So my question is:

Did Caesar ever write the motto "divide et impera" in one of his works or is there some other author who attributes its authorship to him? Or is it rather a formula used by some modern-day historian (and so, who was the first?) to describe the policy he used in the Gallic Wars?

Answer 1

In Caesar the most relevant passage is the following from Book 2 of the Gallic Wars:

Ipse Diviciacum Haedum magnopere cohortatus docet necesse esse manus hostium distineri, ne cum tanta multitudine uno tempore pugnandum sit.

which means:

He (Caesar) explained urgently to Diviciacus of the Aeduans the necessity of dividing the enemy, so that not too many would be fought at one time.

The first record of the idea is found in the Thucydides, Peloponnesian War 1.122. In the Philippics of Demosthenes, the same idea is frequently repeated, although nowhere does he explicitly use the phrase divide and conquer. The first to use the phrase and explicitly describe the idea in detail was probably Machiavelli in his book, The Art of War.