The Causes of the Peloponessian War Ancient Greece during the 4th century B.C. was home to the city-states of Sparta and Athens. These two communities were the superpowers of the region during that time. The peloponnesian war between these two states evolved out of a string of events that would lead to years of conflict. When looking for a single cause of the peloponnesian war none can be found. Over time many events contributed to the eventual war between Sparta and Athens. I believe the peloponnesian war evolved because of Athenian support for Spartan enemies, Spartan alarm at a ris