Zähringen (tsĕr´Ĭng-ən), noble German family. It took its name from a now ruined castle near Freiburg im Breisgau, Baden, and can be traced to the 10th cent. The family held extensive fiefs in Baden and W Switzerland, and Duke Berthold V, one of the most powerful nobles of his era, founded many towns, notably Bern. His death (1218) deprived the family of its Swiss holdings; his domains passed largely to the related Kyburg and Hapsburg families. A younger branch continued in N Baden and split (16th cent.) into the branches of Baden-Baden and Baden-Durlach, reunited in 1771. In 1806, Charles Frederick of Baden was raised to grand ducal rank. Grand Duke Frederick II abdicated in 1918.