Her first marriage, at the age of fifteen, was to the son of her father's rival in Italy, Lothair II, the nominal King of Italy ; the union was part of a political settlement designed to conclude a peace between her father and Hugh of Provence, the father of Lothair.

In 947, Adelaide was married to King Lothair II of Italy.

Two of his sons – Charles the Bald and Louis the German – swore allegiance to each other against their brother – Lothair I – in the Oaths of Strasbourg, and the empire was divided among Louis's three sons ( Treaty of Verdun, 843 ).

Louis was one of Charlemagne's three legitimate sons to survive infancy, including his twin brother, Lothair.

* Lothair was proclaimed and crowned co-emperor in Aachen by his father.

At Worms in 829, Louis gave Charles Alemannia with the title of king or duke ( historians differ on this ), thus enraging his son and co-emperor Lothair, whose promised share was thereby diminished.

At Jonac, he declared Charles king of Aquitaine and deprived Pepin ( he was less harsh with the younger Louis ), restoring the whole rest of the empire to Lothair, not yet involved in the civil war.

Lothair was, however, interested in usurping his father's authority.

While Louis was at Worms gathering a new force, Lothair marched north.

The humiliation to which Louis was then subjected at Notre Dame in Compiègne turned the loyal barons of Austrasia and Saxony against Lothair, and the usurper fled to Burgundy, skirmishing with loyalists near Chalon-sur-Saône.

Lothair was given the choice of which partition he would inherit and he chose the eastern, including Italy, leaving the western for Charles.

According to Nithard's version, both kings first made the same preamble speech, which was a detailed complaint against Lothair.

The Concordat of Worms, which Honorius II helped to draft and which Emperor Lothair III was forced to comply with for Papal support

This was a coup for Honorius, as such a confirmation had never occurred before, and around July 1126 Honorius invited Emperor Lothair to Rome to obtain the imperial title.

Lothair was keen to keep Honorius on his side, keeping to the terms of the Concordat of Worms by not attending episcopal elections, agreeing that the investiture should only occur after the bishop ’ s consecration, and that the oath of homage be replaced with an oath of fidelity.

Lothair was unable to visit Rome immediately as Germany was rocked by the rebellion of the Hohenstaufen brothers, with Conrad Hohenstaufen elected anti-king in December 1127, followed by his descent into Italy and his crowning as King of Italy at Monza on 29 July 1128.

Conrad found little help in Italy and with Honorius ’ support, Lothair was able to keep his throne.

One of the key ecclesiastical advisors of Lothair III was Saint Norbert of Xanten, who travelled to Rome in early 1126 to seek the formal sanction from Honorius to establish a new monastic order, the Premonstratensian Order ( also known as the Norbertines ), which Honorius agreed to do.

Over time, however, Papal dependence on the Holy Roman Emperor was loosened through the quarrels of Louis the Pious and his sons, the future emperor Lothair I, Pepin I of Aquitaine and Louis the German.

When the war between father and sons resumed in Easter 833, Gregory was approached by Lothair, seeking his intervention to bring about reconciliation between Lothair and his father.

When Hilduin was disgraced in 830 for having joined the party of Lothair I, Hincmar accompanied him into exile at Corvey in Saxony, but returned with him to Saint-Denis when the abbot was reconciled with the emperor, and remained faithful to the emperor during his struggle with his sons.

* 841 – In the Battle of Fontenay-en-Puisaye, forces led by Charles the Bald and Louis the German defeat the armies of Lothair I of Italy and Pepin II of Aquitaine.

In 836, however, the family made peace and Louis restored Pepin and Louis, deprived Lothair of all save Italy, and gave it to Charles in a new division, given at the diet of Crémieu.

The subsequent Treaty of Verdun in 843 broke up the empire of Charlemagne, with Lothair retaining the imperial title and control of Italy.

Each of the three brothers was already established in one kingdom: Lothair in Italy, Louis the German in Bavaria, and Charles the Bald in Aquitaine.

* Lothair received the central portion of the empire which later became, from north to south: the Low Countries, Lorraine, Alsace, Burgundy, Provence, and the Kingdom of Italy ( which covered only the northern half of the Italian Peninsula ), collectively called Middle Francia.

Lothair took advantage of Conrad's expedition into Italy and his lack of resources by attacking the Staufens in Germany.

Conrad's failure to make anything of his position in Italy, causing him to return in 1130 without anything to show for it, assured at least a partial victory for Lothair.

The force Lothair took with him into Italy in 1132 was not strong, due to his leaving troops in Germany to prevent the Hohenstaufen from revolting.

In return, they recognized Lothair as emperor, Conrad abandoned his title of King of Italy, and both promised to assist him in another Italian campaign, before a ten-year ‘ Landpeace ’ was declared.

Two main armies, one led by Lothair, the other by Henry the Proud of Bavaria, entered Italy.

Over the next two years, he failed to achieve anything in Italy, however, and returned to Germany in 1130, after Nuremberg and Speyer, two strong cities in his support, fell to Lothair in 1129.

Conrad continued in Lothair's opposition, but he and Frederick were forced to acknowledged Lothair as emperor in 1135, during which time Conrad relinquished his title as King of Italy.

Upon hearing of the French invasion, Otto II ’ s mother Adelaide of Italy, who was Lothair's mother-in-law, sided with Lothair over his own son and moved to the court of her brother King Conrad at Bourgogne.

In 823, Paschal crowned and anointed Lothair I as King of Italy, which set the precedent for the pope ’ s right to crown kings, and to do so in Rome.

In 1130 he was again appointed legate to Germany by Pope Innocent II, where he was instrumental in convincing Lothair III to make two expeditions to Italy for the purpose of protecting Pope Innocent II against the Antipope Anacletus II.

However, Innocent insisted on Bernard's company when he met with Lothair III of Germany.

Lothair became Innocent's strongest ally among the nobility.

When the Salian dynasty ended with Henry V's death in 1125, the princes chose not to elect the next of kin, but rather Lothair, the moderately powerful but already old Duke of Saxony.

Duke Frederick II and Conrad, the two current male Staufer, 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.

As the Welf duke Henry the Proud, son-in-law and heir of Lothair and the most powerful prince in Germany, who had been passed over in the election, refused to acknowledge the new king, Conrad III deprived him of all his territories, giving the Duchy of Saxony to Albert the Bear and that of Bavaria to Leopold IV, Margrave of Austria.

As emperor he included his adult sons, Lothair, Pepin, and Louis, in the government and sought to establish a suitable division of the realm among them.

In 815, he had already given his two eldest sons a share in the government, when he had sent his elder sons Lothair and Pepin to govern Bavaria and Aquitaine respectively, though without the royal titles.

If he died childless, Lothair would inherit his kingdom.

Instead of treating his sons equally in status and land, he elevated his first-born son Lothair above his younger brothers and gave him the largest part of the Empire as his share.

He also made the egregious error of releasing Wala and Adalard from their monastic confinements, placing the former in a position of power in the court of Lothair and the latter in a position in his own house.

With the urging of the vengeful Wala and the cooperation of his brothers, Lothair accused Judith of having committed adultery with Bernard of Septimania, even suggesting Bernard to be the true father of Charles.

Then Lothair finally set out with a large Lombard army, but Louis had promised his sons Louis the German and Pepin of Aquitaine greater shares of the inheritance, prompting them to shift loyalties in favour of their father.

Soon Lothair, with the support of Pope Gregory IV, whom he had confirmed in office without his father's support, joined the revolt in 833.