Poznań is a city in west-central Poland. Located by the Warta River, it is one of the oldest cities in Poland, making it an important historical center. Poznań's impressive cathedral is the earliest church in the country, containing the tombs of the first Polish rulers: duke Mieszko I, king Boleslaus the Brave, king Mieszko II, duke Casimir I the Restorer, duke Przemysł I and king Przemysł II.