The early history of Poland might be thought to begin in the 6th and 8th centuries A.D.
During 6th and 8th centuries lands between the Vistula and Oder Rivers were inhabited by several West Slav tribes. Over time in the long process of struggle for power the most prominent one turned out to be Polanians (Polans or in Polish Polanie). Other tribes included the Vistulanians, Goplans, Opolans, Silesians, Obodritians and Pomeranians.
(How should we link those tribal groups? A question for the historians!)
The begining of the Polish State
There were several strong tribes but after some time of fight for power the
tribe called Polanians (or Polans or in Polish Polanie) came into
prominence. In the middle of the 9th century they started massive expansion to
the neigbouring territories and consequently pushed away Popielid dynasty.
From that period emerges one single ruler Mieszko I of [Piast dynasty]? (born
ca 930 AD). Lands under Duke Mieszko's rule encompassed the following regions:
Greater Poland, probably Lesser Poland, surely Silesia, Eastern Pomerania and
Western Pomerania. The lands totalled to about 250,000 km2 in area, with
population of about 1 million people. Poland's sovereign state
history begins with the duke. Soon he married a Czech princess
Dobrava?, daughter of Bohemian Duke Boleslav I and was baptized
into the Roman branch of Christianity in 966 AD.
This event started widespread conversion to Christianity within Mieszko I realms and was also a
fact of political significance. It marked the incorporation of Poland into the
Christian western world. Moreover he allied with the Czech to make his kingdom
independent from the Germans - in fact he was christianed by Czech clergy and
married to a Czech princess. Poland became a Christian state and the date 966
AD it widely regarded a stepping stone for the future of the whole following
Polish history.
In 967 the Polish ruler defeated German Count Wichman and his allies and in 972 Hodo from the Eastern Marche that enabled Mieszko to take over the West Pomerania. Mieszko I dies in 972 and leaves his son and successor - Boleslaw I Chrobry strong and thriving kingdom.