When the last male member of the Salian dynasty, Emperor Henry V, died without heirs in 1125, a controversy arose about the succession. Duke Frederick II and Conrad, the two current male Staufers, by their mother Agnes, were grandsons of late Emperor Henry IV and nephews of Henry V. Frederick attempted to succeed to the throne of the Holy Roman Emperor (formally known as the King of the Romans) through a customary election, but lost to the Saxon duke Lothair of Supplinburg. A civil war between Frederick's dynasty and Lothair's ended with Frederick's submission in 1134. After Lothair's death in 1137, Frederick's brother Conrad was elected King as Conrad III.