History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
Much mischief had also been caused by the large number of the generals and the division of command—for they had fifteen generals—and the disorder and anarchy among the troops. If only a few men of experience should be chosen as generals, and during this winter they should get the hoplite-force ready, providing arms for those who had none, in order that the number might be as large as possible, and enforcing the general training, in all likelihood, he said, they would get the better of the enemy, if to courage, which they had already, discipline were added when it came to action. For both these things would improve of themselves; their discipline would be practised in the midst of dangers, and their courage, in proportion as their confidence in their skill increased, would prove more self-reliant than ever.
The generals, then, whom they should elect ought to be few in number and clothed with full powers and they should give them their oath that they would in very truth allow them to command according to their judgment; for in this way whatever ought to be kept secret would be better concealed, and their preparations in general would be made in an orderly way and without evasions.