Sobeslaus I, Duke of Bohemia

Soběslav I Oldřich (died 14 February 1140) was one on Bohemia's greatest leaders. He reigned as duke from 1125 to 1140. He was the youngest son of Vratislaus II, the last Bohemian duke to also rule as king.

Soběslav was duke of Brno and Znojmo from 1115 to 1123. He succeeded to the ducal throne only after the death of his brother, Vladislav I. Throughout his reign, he continued to possess the Moravian duchy of Olomouc. Soběslav was also a nationalist partisan and not an ally of the Holy Roman Empire. He was an adversary of the German monarchy throughout his reign and began by using the divisiveness of the election of Lothair of Supplinburg to further Bohemian independence.

When Soběslav decided to withdraw Otto II the Black from Olomouc, one of the Moravian dukedoms, the despoiled prince recoursed to the emperor. Lothair declared that no one could succeed to Bohemia without imperial investiture and proceeded to invade on behalf of Otto, whom he intended to place on the throne. Such, however, was dangerous to the interests of the local nobility and they rallied around Soběslav. On 18 February 1126, a battle occurred near Chlumec, a frontier fortress, between the German and Moravian troops of Lothair and the majority of the Czechs. Soběslav routed Lothair and Otto was even killed in battle. However, the relationship between the two countries returned to the former vassal-suzerain relation.

Soběslav, however, was undermined in Bohemia by his nephew, Bretislaus, son of Bretislaus II. Bretislaus had the support of the Moravian dukes, Conrad II of Znojmo and Vratislaus II of Brno. He also had the support of the church party under Meinhard, bishop of Prague. In June 1130, the conspiracy was discovered and thwarted with much bloodshed. The dukes survived and continued to rule, but Bretislaus was blinded.

Conrad III of Germany tried to amend relations between the two thrones of Bohemia and Germany. He gave Sobeslav the hereditary dignity of archcupbearer of the Empire. His reign saw the foundation of many new German colonies in Czech lands. He died on 14 February 1140 in Hostinev Hradek.