The Duchy of Zähringen was a historical territory in what is now southwestern Germany. Established in the 11th century, it was ruled by the Zähringen family, who played a significant role in the region's development. The duchy included important cities like Bern and Freiburg, which became centers of trade and culture. The Zähringen dynasty expanded its influence through strategic marriages and alliances. However, by the late 12th century, the duchy began to decline, leading to its eventual fragmentation. The legacy of the Duchy of Zähringen can still be seen today in the architecture and cultural heritage of the cities it once encompassed.