It is well known that the ancient Greeks, particularly the ancient Athenians, developed the concept of a democratic government. The basic premise behind a democracy is that the government is formed from the citizens and they all have a say in the decisions that are being made.
Like any form of government, the Athenian democracy had a specific set of rules. Those who went against these rules were deemed to be against the system. In ancient Greece, this is where the concept of ostracism came from. Here’s more information about what ostracism is and how it developed in ancient Greece: