Its founder married Agnes, the daughter of Henry IV, and from their union came a line of kings that included Otto IV and this house's greatest ruler, Frederick II, who became Holy Roman Emperor in 1215.  
With the death of the illegitimate prince Enzio, this house became extinct.  Its penultimate king was another illegitimate son, Manfred, who was the uncle of its last ruler Conradin, who was a king of Sicily.  Its founder married Agnes, the daughter of Henry IV, and from their union came a line of kings that included Otto IV and this house's greatest ruler, Frederick II, who became Holy Roman Emperor in 1215.  FTP, name this German ruling family that arose in the Swabian castle of Staufen.
With the death of the illegitimate prince Enzio, this house became extinct.  
Hohenstaufen