Mieszko I of Poland before his death among a number of princes. They were probably his sons: Bolesław I the Brave, Mieszko and Lambert. In 1999 the archeologist Hanna Kóčka-Krenz located what's left of Mieszko's palace-chapel complex in Poznań. The basic structure of the early Polish state was Mieszko's military force. The ruler managed to create an army composed of about 3,000 mounted warriors. This increasingly powerful force allowed the Polans to attack weaker neighboring tribes and conquer their lands. A key factor promoting cohesion of the growing state was fear of the invaders impressed by them among local populations. The first Piasts reinforced
Mieszko I of Poland poses some problems of interpretation of the information regarding the attack of Margrave Gero on the Slavic tribes, as a result of which he purportedly "subordinated to the authority of the Emperor Lusatia and the Selpuli" (meaning the Słupian tribes) "and also Mieszko with his subjects". According to the majority of modern historians, Thietmar made an error summarizing the chronicle of Widukind, placing the Gero raid there instead of the fighting that Mieszko conducted at that time against Wichmann the Younger. Other sources make no mention of such conquest and of putting the Polans state on the same footing with