Duke Berthold I was a notable nobleman in the medieval period, serving as the Duke of Zähringen from around 1090 until his death in 1122. He played a significant role in the expansion of his family's influence in Swabia and Burgundy, establishing several towns and promoting trade in the region. His leadership helped to strengthen the political landscape of the time. Berthold I was also known for his support of the Church and involvement in various military campaigns. He was a key figure in the Investiture Controversy, a conflict between the papacy and secular rulers over the appointment of church officials. His legacy continued through his descendants, who maintained the family's prominence in European history.