The sole member of the house of Supplinburg to hold the titles, Lothar II (1075-1137) became duke of Saxony in 1106, king of Germany in 1125 and Holy Roman Emperor in 1133.

Lothar faced opposition through most of his reign from Frederick II, the Hohenstaufen duke of Swabia, whom he had defeated in the election to the kingship (the usual preliminary to accession as emperor), and Frederick's brother Conrad III.

Elected as rival king (1127), Conrad submitted to Lothar only in 1135. After Lothar's death, he was elected (1138) king of the Romans, ruling as emperor in all but name, though he was never crowned as such.

The son of Gebhard, count of Supplinburg, and Hedwig, countess of Formbach, Lothar married Richensia of Nordheim. Their daughter Gertrude married Henry the Proud, duke of Saxony and Bavaria. Lothar is entombed in the monastery church of Königslutter.

Preceded by:
Henry V, Holy Roman Emperor
List of German Kings and Emperors Succeeded by:
Conrad III, King of the Romans