Mieszko I of Poland Pomerania, eventually conquering it up to the vicinity of the lower Oder river. During the last years of his life, he fought the Bohemian state, winning Silesia and probably Lesser Poland. Mieszko I's alliance with the Czech prince, Boleslaus I the Cruel, strengthened by his marriage in 965 to the Czech Přemyslid princess Dobrawa, and his baptism in 966 put him and his country in the cultural sphere of Western Christianity. Apart from the great conquests accomplished during his reign (which proved to be fundamental for the future of Poland) Mieszko I was renowned for his internal reforms, aimed at
Mieszko I of Poland to the Warta River). In all probability Mieszko decided to pay tribute in order to avoid an invasion similar to the one that Lusatia had suffered. This homage would take place in 965, or in 966 at the latest. Very likely the tribute applied only to the Lubusz land, which was in the German sphere of influence. This understanding of the tribute issue explains why already in 967 Mieszko I was described in the Saxon chronicles as the Emperor's friend (or ally, supporter, Latin: "amicus imperatoris"). Probably in 964 Mieszko began negotiations with the Bohemian ruler Boleslav I the Cruel.