[4] Upon the disputed Papal election of 1159 and the succeeding schism, King Henry II established closer ties to the Holy Roman Empire, particularly when he himself came into conflict with the English clergy led by Thomas Becket, Archbishop of Canterbury; this was reflected at the beginning of 1165, when Frederick I, Holy Roman Emperor sent an embassy led by Rainald of Dassel, Archbishop of Cologne to the English court, with the purpose of arranging a double marriage between the two daughters of Henry II, Matilda and Eleanor, with the Emperor's son Frederick V, Duke of Swabia and Henry the Lion, Duke of Saxony (the Emperor's cousin and one of the most powerful German princes of his time) respectively.

[4] There was conflict during the negotiations, however, when Robert de Beaumont, 2nd Earl of Leicester refused to greet the German archbishop, alleging him to be a schismatic and a supporter of the anti-pope, Victor IV.

[3] Preparations for the wedding began shortly after Matilda's return and the departure of the embassy, which is probably recorded in the register of English knights-tenants and their possessions, contained in the "red" and "black" books of the treasury, and drawn up in order to assess the aid collected by the King for the marriage of his daughter.

At the beginning of 1167, the Duke of Saxony sent an embassy to deliver the bride to him; Matilda, accompanied by her mother, sailed from Dover to Normandy on Michael's Day (29 September), and from there, probably after Christmas, set off for Germany.

They had Brunswick Cathedral erected from 1173 onwards and initiated the Lucidarius, the first original German-language work in prose, as well as the Gospels of Henry the Lion, a masterpiece of Romanesque book illumination.

In 1180, the latent conflict that had arisen a few years earlier between Henry the Lion and Emperor Frederick I finally reached its climax when the Duke of Saxony was tried in absentia for insubordination by a court of bishops and princes at Würzburg in 1180 and stripped of his lands and declared an outlaw.

[3] Henry the Lion refused to submit, and the Emperor laid siege to Brunswick, within the walls of which Matilda just gave birth to her second son, named Lothair.