Aratus (24.5-25.1)

For he considered that the Greek states which were weak would be preserved by mutual support when once they had been bound as it were by the common interest, and that just as the members of the body have a common life and breath because they cleave together in a common growth, but when they are drawn apart and become separate they wither away and decay, in like manner the several states are ruined by those who dissever their common bonds, but are augmented by mutual support, when they become parts of a great whole and enjoy a common foresight.

And so, since he saw that the best of the neighbouring peoples were autonomous, and was distressed at the servitude of the Argives, he plotted to kill Aristomachus the tyrant of Argos, being ambitious to restore its freedom to the city as a reward for the rearing it had given him, as well as to attach it to the Achaean League.