LOTARIO III of Suplinburgo, ROMAN EMPEROR, king of GERMANY. — Elected at Mainz on 30 August 1125, he died at Breitwang in Tyrol on 4 December 1137. He was of minor nobility, but had risen to power thanks to the protection of Enrico V, whom he had helped in the rebellion against his father. His reward had been the Duchy of Saxony and subsequently the Margraviates of Meissen and Lusatia; later, however, he had opposed the Emperor. Upon the death of Enrico V, the archbishop of Mainz, Adalbert, set his sights on him in order to oppose the candidacy of Federico of Swabia, nephew of the deceased emperor. Several apostolic legates attended his election, and L. was regarded as the Church’s protégé. His election provoked discontent in various regions of Germany; Federico of Swabia declared his opposition, and L. proceeded harshly against him, placing him under the ban of the Empire. Federico then relinquished his rights to his brother Corrado, who had himself elected king by his followers and subsequently descended into Italy to have himself recognized as king and crowned at Milan.
The struggle between the two rivals lasted a very long time; only in 1135 did Federico and Corrado of Swabia resign themselves to recognizing Lotario’s superiority. He had emerged victorious thanks to the support of Pope Innocenzo II. Indeed, when in 1130, upon the death of Onofrio II, the College of Cardinals divided and the two elections of Innocenzo II and Anacleto II took place, L., following the example of the kings of France and England, recognized as the true pope Innocenzo II, who enjoyed the influential support of s. Bernardo. At the Conference of Liège (1131), L. and Innocenzo II reached an agreement: the Pope recognized L. as king and promised to crown him emperor after he had been brought back to Rome by the royal forces, which would expel the antipope. Innocenzo II nevertheless refused to abandon the Concordat of Worms, as L. wished.
L. descended into Italy in 1132 and, together with s. Bernardo, led the Pope to Rome, where he was crowned emperor at St John Lateran (4 June 1133), since St Peter’s was occupied by the partisans of Anacleto I. The question of the Concordat of Worms was again discussed, but Innocenzo II and s. Bernardo were uncompromising in defending II. Instead, the question of the Matildine possessions was settled: L. was to hold them in fief, and after him so was his son-in-law, the duke of Bavaria; upon their deaths they would return to the Holy See.
L. returned to Italy in 1136, in response to the appeal of Innocenzo II, who had remained isolated in the face of the bloc formed by Anacleto II and his protector Ruggero II, king of Sicily. This time it was necessary to avoid Rome altogether: at San Severo, L. and Innocenzo II jointly and in agreement invested Rinaldo of Alife with the Duchy of Apulia; they then advanced as far as Bari, but Ruggero II withdrew to Sicily, avoiding the confrontation, and L.’s expedition failed. He died on the return journey to Germany.