"Polish tribes" is a term used sometimes to describe the tribes of West Slavs that lived in the territories that became Polish from around the mid-6th century to the creation of Polish state by the Piast dynasty. The territory they lived on became a part of the first Polish state created by duke Mieszko I and expanded at the end of the 10th century, enlarged further by king Bolesław I at the beginning of the 11th century. The Polish tribes are grouped together with East Slavic and South Slavic tribes as the Early Slavs with varying degrees of common ancestry and culture.
In about 850 AD a list of peoples was written down by the Bavarian Geographer. Absent on the list are Polans, Pomeranians and Masovians, who were mentioned later by Nestor the Chronicler in his Primary Chronicle (11th/12th century).
The most important Polish tribes were Polans, Masovians, Vistulans, Silesians and Pomeranians. These five tribes "shared fundamentally common culture and language and were considerably more closely related to one another than were the Germanic tribes."
The name "Poland" is derived from the most powerful of the tribes - the Polans. Their name, in turn, derives from the word pole - field. It was also used for the eastern Polans that lived in the region of the Dnieper River.