Lothair II, also called Lothair III, 1075–1137, Holy Roman emperor (1133–37) and German king (1125–37); successor of Holy Roman Emperor Henry V. His predecessor invested him with the duchy of Saxony in 1106, but after 1112 Lothair, in several rebellions, successfully championed local independence against the royal authority. When Henry V died (1125), the electors chose Lothair over Frederick of Hohenstaufen, Henry V’s nephew, to succeed him; this represented an important victory of elective over hereditary kingship. Frederick and his brother Conrad (who later became German king as Conrad III) made war on Lothair, and Conrad was elected (1127) antiking. However, Lothair and his son-in-law, Henry the Proud of Bavaria, defeated the Hohenstaufen and peace was made in 1135. In Italy, Lothair promised his support to Pope Innocent II, whose election was disputed. In 1132 he entered Italy and was crowned emperor in Rome (1133). After the defeat of the Hohenstaufen he returned (1136) to Italy and campaigned successfully against Roger II of Sicily, supporter of the antipope Anacletus II. Lothair died on the journey home. As emperor, Lothair adhered loyally to the Concordat of Worms (see Worms, Concordat of), and actively supported both political expansion and revival of missionary activity in the East. He forced various heathen princes to pay tribute and established German suzerainty in Denmark, Bohemia, and Poland (see Boleslaus III). At his death his rival, Conrad III, was elected king. Lothair is known also as Lothair of Saxony or Lothair of Supplinburg.