The Clouds represents a departure from the main themes of Aristophanes' early plays – Athenian politics, the Peloponnesian War and the need for peace with Sparta. The Spartans had recently stopped their annual invasions of Attica after the Athenians had taken Spartan hostages in the Battle of Sphacteria in 425 and this, coupled with a defeat suffered by the Athenians at the Battle of Delium in 424, had provided the right conditions for a truce. Thus the original production of The Clouds in 423 BC came at a time when Athens was looking forward to a period of peace. Cleon, the populist leader of the pro-war faction in Athens, was a target in all Aristophanes' early plays and his attempts to prosecute Aristophanes for slander in 426 had merely added fuel to the fire. Aristophanes however had singled Cleon out for special treatment in his previous play The Knights in 424 and there are relatively few references to him in The Clouds.
Freed from political and war-time issues, Aristophanes focuses in The Clouds on a broader issue that underlies many conflicts depicted in his plays – the issue of Old versus New, or the battle of ideas.[10] The scientific speculations of Ionian thinkers such as Thales in the sixth century were becoming commonplace knowledge in Aristophanes' time and this had led, for instance, to a growing belief that civilized society was not a gift from the gods but rather had developed gradually from primitive man's animal-like existence.[11] Around the time that The Clouds was produced, Democritus at Abdera was developing an atomistic theory of the cosmos and Hippocrates at Cos was establishing an empirical and science-like approach to medicine. Anaxagoras, whose works were studied by Socrates, was living in Athens when Aristophanes was a youth. Anaxagoras enjoyed the patronage of influential figures such as Pericles, but oligarchic elements also had political advocates and Anaxagoras was charged with impiety and expelled from Athens around 437 BC.
The battle of ideas had led to some unlikely friendships that cut across personal and class differences, such as between the socially alert Pericles and the unworldly Anaxagoras, and between the handsome aristocrat, Alcibiades, and the ugly plebeian, Socrates. Socrates moreover had distinguished himself from the crowd by his heroism in the retreat from the Battle of Delium and this might have further singled him out for ridicule among his comrades.[12] He was forty-five years old and in good physical shape when The Clouds was produced[13] yet he had a face that lent itself easily to caricature by mask-makers, possibly a contributing reason for the frequent characterization of him by comic poets.[14] In fact one of the plays that defeated The Clouds in 423 was called Connus, written by Ameipsias, and it too lampooned Socrates.[15] There is a famous story, as reported for example by Aelian, according to which Socrates cheerfully rose from his seat during the performance of The Clouds and stood in silent answer to the whispers among foreigners in the festival audience: "Who is Socrates?"[16]
