[6] So as to control Upper Burgundy, Hugh decided to marry his son Lothair II, the nominal King of Italy,[7] to the 15-year-old Adelaide (in 947, before 27 June).

The calendar of saints states that Lothair was poisoned on 22 November 950 in Turin by the holder of real power, his successor, Berengar II of Italy.

After a time spent in the marshes nearby, she was rescued by a priest and taken to a "certain impregnable fortress," likely the fortified town of Canossa Castle near Reggio.

A few years later, in 953, Liudolf, Duke of Swabia, Otto's son by his first marriage, instigated a big revolt that was quelled by his father.

After returning to Germany with his new wife, Otto cemented the Holy Roman Empire by defeating the Hungarian invaders at the Battle of Lechfeld on 10 August 955.

[11] Adelaide accompanied her husband on his second expedition to Italy to subdue the revolt of Berengar II and to protect Pope John XII.

The ordo presents a theological and political concept that legitimizes the empress's status as a divinely ordained component of the earthly rule.

Crucial to Otto's establishing legitimacy in his conquest of Italy and in bringing the imperial crown to the couple, was the support of Adelaide and her extensive network of relations.

Otto II was crowned co-emperor in 967, then married the Byzantine princess Theophanu in April 972, resolving the conflict between the two empires in southern Italy and ensuring the imperial succession.

Another pleader was Gerbert of Aurillac, at that time archbishop of Reims (the later Pope Sylvester II), who wrote to Adelaide to ask for protection against his enemies.

However, Adelaide was in conflict with her daughter-in-law, the Byzantine princess Theophanu, as only one woman could be queen and hold the associated functions and powers at court.

Engelberge greatly influenced her husband, Emperor Louis II, in his attempts to extend imperial control to southern Italy in the 870s.

"[18] After being expelled from court by Otto II in 978, she divided her time between living in Italy in the royal palace of Pavia[19] and Arles with her brother Conrad I, King of Burgundy, through whom she was finally reconciled with her son.

The narrative claims that Adelaide returned from Lombardy to join with Theophanu, Matilda, and other leaders of Europe and reclaim the child.

[21] When Theophanu died in 990, Adelaide assumed regency on behalf of Otto III until he reached legal majority four years later.

[23] Thietmar of Merseburg reports that Otto III dismissed his grandmother after his mother's death, but Althoff doubts this story.

[26][27] Adelaide had long entertained close relations with Cluny, then the center of the movement for ecclesiastical reform, and in particular with its abbots Majolus and Odilo.

[28] On her way to Burgundy to support her nephew Rudolf III against a rebellion, she died at Selz Abbey on 16 December 999, days short of the millennium she thought would bring the Second Coming of Christ.

She was thus a principal agent — almost an embodiment — of the work of the pre-schism Church at the end of the Early Middle Ages in the construction of the religious culture of Central Europe.

[32] The union produced one child: In 951, Adelaide was married to King Otto I, the future Holy Roman Emperor.

The most famous representation of Adelaide in German art belongs to a group of sandstone figures in the choir of Meissen Cathedral, which was created around 1260.