The House of Frohburg (also Froburg) was a noble family in medieval Switzerland, with possessions in what is now the canton of Solothurn. They originate in the Wigger basin, near Zofingen. In the 10th century, they built Frohburg Castle on a hill near Trimbach.
They had the title of counts from the later 11th century. They ruled the lands between Olten and Solothurn, and took parts of Aargau and Sisgau as fief from the bishop of Basel.
They reached the peak of their power in the later 12th and early 13th century, building a number of castles, and founding towns such as Aarburg, Liestal, Olten (then a fortified river crossing), Waldenburg, Wiedlisbach and Zofingen. They also founded Schöntal Abbey near Waldenburg.
The House of Frohburg was divided into three branches, Neu-Homberg, Waldenburg and Zofingen, in c. 1250.
The Zofingen branch was extinct in 1307, followed by the Neo-Homberg one in 1325. The Waldenburg branch survived for another 40 years but declined in influence, being forced to sell most of its possessions, most of them to the ascending House of Habsburg.
The last count of Frohburg was Hermann VI (d. 1367 as abbot of St. Urban's Abbey).
Counts of Frohburg
House of Frohburg
Partitions of Frohburg under House of Frohburg rule
Possibly sons of Adalbero. They may have ruled jointly. In 1114, another Volmar is mentioned, but is not identical with Volmar I. This new Volmar appears as co-ruler with Volmar I and his brother Louis. Louis' son, Ortlieb, would become Bishop of Basel.
Children of Herman II, divided the land. Louis III was the founder of the Zofingen branch, with lands in the canton of Aargau. According to some theories, Gertrude, wife of King Rudolf I of Germany, was his daughter.
Herman III founded the Waldenburg branch, with lands in the canton of Basel. The other two brothers did not take part on the divisions. One of them, Ulrich, pursued an ecclesiastical career being an abbot at Frienisberg Abbey.
Children of Louis III, probably divided fiefs in their father's lifetime: while Louis IV kept co-ruling with his father, Herman IV founded a new branch of the family at Homberg, by inheriting, through marriage, this land.
Maria of Oettingen (d. 10 July 1369) 11 June 1315 or 6 April 1316 two children
Children of Louis I and Elisabeth of Rapperswil, ruled jointly with their cousin Herman II (son of Werner I). Werner inherited his mother's fiefs in the canton of Schwyz, and was also a Minnesinger.
Adelaide of Ramstein (d. bet. 17 October 1367-29 May 1371) 3 November 1326 no children
Sons of Volmar IV, probably ruled jointly. Herman was also abbot of St. Urban Abbey. After both deaths with no descendants, their line died out. Their properties were sold to the Count of Nidau and the Bishop of Basel.
