Mieszko I and Boleslaw Chrobry (Boleslaus the Brave)

The reigns of Mieszko I (?-992) and his son Boles³aw Chrobry (Boleslaus the Brave), mark the period when the Polish tribes were brought together in a united and internally well-knit realm which made an active contribution to European politics. Assisted by the ecclesiastical authorities, between 972 and 990 the principality of Poland grew, absorbing Pomerania, Lesser Poland (Polonia Minor), and Silesia by way of military conquest,

Denarius of Boleslaus the Brave

the pursuit of trade, marriage alliances, and the foundation of an administrative system. Most importantly, the new state gained a foothold on the international scene. The wars skilfully conducted by Mieszko and Boleslaus earned Poland not only new territories (the Strongholds of Czerwieñ and, temporarily, Moravia and Lusatia), but also the reputation of a power to be reckoned with even by the Holy Roman Emperor. The major success of  early Piastian foreign policy was the Congress of Gniezno (1000), during which the Emperor Otto III recognised Boleslaus as the principal ally for his plan to unite Europe under the imperial rule, and approved the erection of an independent Polish metropolitan see, as well as Boleslaus' subsequent coronation (1025).