Text: The region that would become Poland, a great plain sandwiched between the Vistula and Odra rivers, has been inhabited since the Stone Age by migratory tribal peoples among them Celts, Balts, Huns, Slavs and Mongols.
Entailment: Celts are among the people who have settled in what is now Poland.
Contradiction: The region that is now Poland has not been home to Slavs.