Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

45. They delivered their message to the council, adding that they came with full power to 'treat¹ about all differences. Alcibiades took alarm; he feared that if the envoys made a similar statement to the people they would win them over to their side, and that the Argive alliance would be rejected. Whereupon he devised the following trick: [2] he solemnly assured the Lacedaemonians that if they would not communicate to the people the extent of their powers, he would restore Pylos to them, for he would use his influence in their favour instead of against them, and would arrange their other differences. [3] But his real aim all the time was to alienate them from Nicias, and to bring about an alliance with Argos, Elis, and Mantinea, which he hoped to effect, if he could only discredit them in the assembly, and create the impression that their intentions were not honest, and that they never told the same tale twice. And he succeeded; [4] for when the envoys appeared before the assembly, and in answer to the question whether they had full powers replied 'No,' in direct contradiction to what they had said in the council, the patience of the Athenians was exhausted, and Alcibiades declaimed against the Lacedaemonians more violently than ever. The people were carried away and were ready to have in the Argives, and make an alliance with them and their confederates on the spot. But an earthquake occurred before the final vote was taken, and the assembly was adjourned.