Thukydides 4.124
In all there were about three thousand Hellenic heavy infantry, accompanied by all the Macedonian cavalry with the Chalcidians
<also Hellenes>, near one thousand strong, besides an immense crowd of Barbarians.
A separation among Macedonians and Barbarians (non-Greeks) also in 4.125.1-2:
But in consequence of their dispute nothing had been determined as to when they should set out; and when night came on the Macedonians and the mass of the Barbarians immediately took fright, as large armies are wont to be smitten with unaccountable panic... Perdikkas, who at first was not aware of their movement, was compelled, when he did learn of it, to go away without seeing Brasidas;...
And perhaps in 4.127.2:
Thereupon most of the Barbarians refrained from attacking the Hellenes under Brasidas in the open country, and leaving a portion of their force to follow and harass them, the rest advanced on the run after the fleeing Macedonians, slew them as they came upon them, and getting ahead of them occupied the narrow pass between two hills which lead into the country of Arrabaios...