Potidaea was a colony of Corinth on the Chalcidice peninsula, but was a member of the Delian League and paid tribute to Athens. After Sybota, Athens demanded that Potidaea pull down part of its walls, expel Corinthian ambassadors, and send hostages to Athens. Athens was afraid that Potidaea would revolt due to Corinthian or Macedonian influence, as Perdiccas II of Macedon was encouraging revolts among Athens' other allies in Thrace.