Earlier, in the second year of this war, a plague struck  Athens, killing Pericles.
One leader in this conflict, Nicias, arranged for a fifty-year truce, however, this was  broken when Alcibiades convinced one side to launch the Sicilian Expedition. Partly  because of the removal of Alcibiades from the expedition, it utterly failed, and much  of the Athenian navy was lost. Earlier, in the second year of this war, a plague struck  Athens, killing Pericles. FTP identify this war between the Delian League and Sparta  and her allies.
One leader in this conflict, Nicias, arranged for a fifty-year truce, however, this was  broken when Alcibiades convinced one side to launch the Sicilian Expedition.
Peloponnesian War