Some historians and archaeologists consider the area the heart of the first state of the Polans, the "founding" tribe of Poland.
Some have suggested that the use of water is an allusion to the baptism of Mieszko I, the Duke of Polans (c. 935–992) in 966 AD, uniting all of Poland under the banner of Christianity.
Among these tribes were the Vistulans (Wiślanie) in southern Poland, with Kraków and Wiślica as their main centers (major fortified centers were built in their country in the 9th century), but later the tribe(s) referred to as the Polans (Polanie—literally, "people of the fields") would prove of decisive historic importance.
By conquest the first leaders of the Polans, Mieszko I and especially Boleslaw I added a number of surrounding territories to the newly established core Polish state, and Lebus Land or Lubusz in Lusatia came under Polish rule.
The West Slavic Polans had established a state east of the Saxon marches and, aiming to advance into the Pomeranian lands north of the Warta river, had reached an agreement with late Margrave Gero and Emperor Otto I: Mieszko's ducal title was confirmed and the Polans paid a recurring tribute to the emperor, which was collected by Margrave Odo.