Battle of Chlumec (1126)

The Battle of Chlumec represented the culmination of rivalries between two most important members of the Přemyslid dynasty at the time: Soběslav I, King of Bohemia, and Otto II the Black, appanage prince of Olomouc. Shortly before his death in 1125, Duke Vladislaus I chose Soběslav as his successor, although according to the Seniority Law Otto was next in the line of succession, as the oldest living member of the Přemyslid dynasty. Moreover, shortly after ascending the throne, Soběslav relieved his competitor of the administration of Brno, which weakened his position in Moravia. Otto left the country and demanded the Bohemian throne from Lothair III, King of the Romans. The latter acknowledged his claim and in winter of the same year led a military campaign to depose Soběslav.

Soběslav soon learnt of Lothair’s plans and prepared well for the oncoming war. He skilfully used the means of propaganda available at the time, presenting the war with the King of the Romans as a threat to the whole country, whose destiny he commended to its patron saints. He took the spear of Saint Wenceslas from Saint Vitus Cathedral in Prague, attaching to it the alleged flag of Saint Adalbert. The ducal chaplain then took both relics to the battle. It was one of the most powerful manifestations of the idea of Czech statehood ever.

Lothair’s army entered Bohemia on 16 February through the Ore Mountains, but its progress was hampered by the thawing season and bad visibility. His vanguard was attacked two days later by Soběslav’s detachments in a pass near the Chlumec fort. They killed most of them – approximately 500 fighters, including many noblemen. One of the casualties was Otto the Black himself. After that, Soběslav surrounded the rest of Lothair’s army and showed his prudence; instead of inflicting a crushing defeat on the enemy, which would have provokeed a war with the Empire, he made peace with the King of the Romans and swore an oath to him. Thus he earned a recognition of his rule and the status of an important ally of Lothair’s, which significantly contributed to the stable development of the Czech state in the following decades. As an expression of gratitude for his victory, after the battle he had the Rotunda of Saint George on Říp Mountain consecrated again.