Nicias (/ˈnɪʃiəs/; Ancient Greek: Νικίας Νικηράτου Κυδαντίδης, romanized: Nikias Nikēratou Kydantidēs; c. 470–413 BC)[a] was an Athenian politician and general, who was prominent during the Peloponnesian War.

A slaveowning member of the Athenian aristocracy, he inherited a large fortune from his father, and had investments in the silver mines around Laurion, in south-east Attica.

Following the death of Pericles in 429 BC, Nicias became the principal rival of Cleon and the democrats in the struggle for political leadership of the Athenian state.

[1] Xenophon wrote of "how once on a time Nicias, the son of Niceratus, owned a thousand men [slaves] in the silver mines, whom he let out to Sosias, a Thracian".

He was also considered respectable, given his family background, and he was acknowledged to be well acquainted with military details; but perhaps his strongest quality was his devoutly unscrupulous devotion to religion.

[citation needed] Cleon then effectively ended the truce between Athens and Sparta after he resolved to rescue the town of Amphipolis in Macedonia.

[citation needed] Historians A. W. Gomme and Raphael Sealey believed, as Thucydides reported, that Alcibiades was "offended with the Lacedaemonians for having negotiated the treaty through Nicias and Laches, and having overlooked him on account of his youth".

[5][6][7] Disputes over the interpretation of the treaty led the Spartans to dispatch ambassadors to Athens with full powers to arrange all unsettled matters.

The Athenians initially received these ambassadors well, but Alcibiades met with them in secret before they were to speak to the Ecclesia and told them that the Assembly was haughty and had great ambitions.

This was in direct contradiction to what they had said the day before, and Alcibiades seized on this opportunity to denounce their character, cast suspicion on their aims, and destroy their credibility.

He took advantage of his increasing power to orchestrate the creation of an alliance between Argos, Elis, Mantinea, and other states in the Peloponnese, threatening Sparta's dominance in the region.

[13] In 415 BCE, delegates from the Sicilian city of Segesta (Egesta) arrived in Athens to plead for the support of the Athenians in their war against Selinus.

[citation needed] During the subsequent debates, Nicias vehemently opposed an Athenian intervention, using the argument that the campaign would be excessively costly if it was to be successful.

[citation needed] Alcibiades argued that a Sicilian campaign would bring riches to the city and expand the empire, just as the Persian Wars had.

[citation needed] It was at Nicias' suggestion that the size of the fleet was significantly increased from 60 ships to "140 triremes, 5,100 hoplites, and about 1,300 archers, slingers, and light armed men".

[14] Nicias' intention may have been to shock the Ecclesia with his high estimate of the forces required, but, instead of dissuading his fellow citizens, his analysis made them all the more eager, and the campaign motion was carried.

[citation needed] Most of the surviving Athenian soldiers were kept in the stone quarries near Syracuse (as there was no other room for them), where many died slowly of disease and starvation.