The three great schisms in Christianity is bishops , communication , wars.
Athenians ostracized the citizens that would endanger the city or the community or if the person ostracized was a tyrant. Being ostracized meant being banished from the city for a time period that they would decide. Sometime for a few years, sometime for life.
1945 to 1989 spans the period of communist rule imposed by the Soviets over Poland after the end of World War II. These years, while featuring general industrialization, urbanization and many improvements in the standard of living, were marred by Stalinist repressions, social unrest, political strife and severe economic difficulties.