History of the Peloponnesian War

Foremost amongst these was Alcibiades, son of Clinias, a man yet young in years for any other Hellenic city, but distinguished by the splendor of his ancestry. Alcibiades thought the Argive alliance really preferable, not that personal pique had not also a great deal to do with his opposition; he being offended with the Lacedaemonians for having negotiated the treaty through Nicias and Laches, and having overlooked him on account of his youth, and also for not having shown him the respect due to the ancient connection of his family with them as their Proxeni, which, renounced by his grandfather, he had lately himself thought to renew by his attentions to their prisoners taken in the island.

Being thus, as he thought, slighted on all hands, he had in the first instance spoken against the treaty, saying that the Lacedaemonians were not to be trusted, but that they only treated, in order to be enabled by this means to crush Argos, and afterwards to attack Athens alone; and now, immediately upon the above breach occurring, he sent privately to the Argives, telling them to come as quickly as possible to Athens, accompanied by the Mantineans and Eleans, with proposals of alliance; as the moment was propitious and he himself would do all he could to help them.

Upon receiving this message and discovering that the Athenians, far from being privy to the Boeotian alliance, were involved in a serious quarrel with the Lacedaemonians, the Argives paid no further attention to the embassy which they had just sent to Lacedaemon on the subject of the treaty, and began to incline rather towards the Athenians, reflecting that, in the event of war, they would thus have on their side a city that was not only an ancient ally of Argos, but a sister democracy and very powerful at sea.