For harmony makes small states great, while discord undermines the mightiest empires.

[Nam concordia parvae res crescunt, discordia maxumae dilabuntur.]

Sallust (c. 86-35 BC) Roman historian and politician [Gaius Sallustius Crispus]

The War with Jugurtha [Bellum Iugurthinum], Part 10 [tr. Loeb (1921)]