Odyssey - Ancient History Documentaries

How Paranoia Killed The Spartan-Athenian Alliance | The Spartans (1x14)

:

Athens, which had been allied with Sparta against Persia, begins to experience an expanded economy (and democracy under the leadership of Pericles). His construction of the long walls - fortifications which connect Athens to Piraeus - is considered to be a hostile act by an increasingly paranoid Sparta, and is the basis for future discord between the two states.