 Under pressure, the extremist leaders opened peace negotiations with Sparta and began constructing a fortification in the harbor of Piraeus, which they might have considered handing over to the Spartans.After the leader of the extremists, Phrynichus, was assassinated, the moderates grew bolder and arrested an extremist general in Piraeus.A confrontation ensued, which ended with the hoplites in Piraeus tearing down the new fortification.