War with Otto I Under Boleslaus's rule, Bohemia renounced the rule of the Eastern Franks's raging war with Otto the Great, the eldest son of Henry I. This war rejuvenated a newfound sense of unity within the kingdom as they came together to fight against the East Frankish Empire pushing them out of Prague. Boleslaus stopped the payment shortly after he ascended the throne, which led to this war with King
Otto. In 935, Boleslaus attacked the
Thuringian allies of the Saxons in the northwest and defeated two of Otto's armies (from Thuringia and
Merseburg). The war then deteriorated to border raids (the general pattern of warfare in this region at the time) and reached its conclusion in 950, when King Otto besieged a castle owned by Boleslaus's son, Boleslaus II. This prompted Boleslaus to sign a peace treaty with Otto. Although he remained undefeated, he promised to resume the payment of tribute. However, because of his success against the Eastern Franks, Boleslaus would become a great ally to Otto the Great in his later conquest.
Military conquests Five years after the war with Otto, Boleslaus and the armies of the Bohemians and Franks allied against the Magyars in the victorious
Battle of Lechfeld. After the battle, the remainder of the huge Magyar army turned to Bohemia, where it was crushed by Boleslaus. He had also helped Otto to crush an uprising of
Slavic tribes led by the
Obotrite princes
Nakon and
Stojgněv on the Lower
Elbe river in the
Battle on the Raxa. The defeat of the invading Hungarians brought the same benefits to both Franks and Bohemians. Less obvious is what Boleslaus expected to gain from his participation in Otto's war against the Obotrite princes in the far north. He probably wanted to ensure that his powerful Frankish neighbors did not interfere with him in expanding the Bohemian territories to the east. As a result of the victory, Boleslaus freed the
Moravian lands from Magyar raids and expanded his territory, which in turn was later conquered by
Polish dukes and became known as
Upper Silesia and
Lesser Poland. By occupying the city of
Kraków, he controlled important trade routes from Prague to
Kiev and
Lviv. He even allied with Mieszko in the campaign against the Saxon count
Wichmann the Younger. Boleslaus was ambitious in his conquest gaining many new territories for Bohemia. It was under Boleslaus that the “hradská soustava” system was created. In this system, strongholds are built all along the countryside. These strongholds were integral for keeping governance over the land, each castle holding importance whether militaristic, political, or religious. As the Bohemian territory expanded, so did the expansion of Christianity in those territories.
Religious expansion Despite his violent rise to power and aggressive ruling style that differed heavily from his predecessors, Boleslaus I kept strong ties with the Roman Catholic Church throughout his reign and played a part in further Catholicizing Eastern Europe. Similarly to his predecessors, Duke Boleslaus I had several religious institutions built throughout Bohemia. Flour, tin, slaves, and furs were desired among the Rus, Slavs, Turks, and Jews who are recorded to have traveled to Bohemia to trade for these goods. During the reign of the Boleslaus I, Prague was a production center as well, producing items like saddles, bridles, and shields. Bohemia also produced kerchiefs which were very thin and of no functional use but were used as precious items for trading. The expansive system of trade and production in Prague indicates cultural connections and foreign relationships that existed during the reign of Boleslaus I. Trading with foreign lands and people likely contributed to the spread of Christianity to Bohemia's trading partners, further indicating a focus on Christianization under the rule of Boleslaus I. Boleslaus I and his predecessors are also known to have built churches, monasteries, and strongholds in the city of Prague. Medieval religious institutions were very wealthy and important in building both the city and Bohemia's population and economy. The growing economic strength Bohemia while Duke Boleslaus I was in power built stability and influence which he would use in his efforts to centralize Bohemian power. == Marriage and children ==