She played an active role in promoting her son, Duke Conrad the Younger, as a candidate for the German throne in 1024 and to this end corresponded with King Mieszko II Lambert of Poland.

[3] Their marriage was possibly consanguineous[4] and therefore was condemned by Henry II (her father's rival who was now crowned German king) at the Synod of Thionville in January 1003.

Instead King Henry II ceded the duchy to Count Adalbero of Eppenstein, who was married to Matilda's sister, Beatrice.

Conrad the Younger refused to accept the new king and his mother Matilda, with her second husband Frederick and his Lorraine entourage, left the site in protest.

While Mieszko's rule was not only questioned by Conrad but also by his own Piast relatives, Matilda presented him with a valuable liturgical manuscript (the Liber de Officiis divinis).

The dedicatory page of the book contained a letter from Matilda to Mieszko (Epistola ad Mathildis Suevae Misegonem II Poloniae Regem) in which she named him a distinguished king, praised him for his building of new churches, and knowledge of Latin, and wished him strength against his enemies.

[12] The dedicatory page also contained a miniature depicting Matilda giving the book to Mieszko, who is shown wearing a crown and seated on a throne.

Matilda died sometime after Easter 1030 (when she was at the imperial court) and before January 1034, when Emperor Conrad II issued a diploma at the intervention of his wife Gisela, commemorating her death.