After her father's early death in 1301, Beatrice and her siblings were placed under the tutelage of their maternal uncle
Herman, Margrave of Brandenburg-Salzwedel until 1305, when the oldest son of Bolko I, Bernard, assumed the government of his domains and the guardianship of his younger siblings, including Beatrix. It was this brother Bernard who, wanting to secure an alliance with Bavaria, arranged Beatrice's marriage to
Louis IV, Duke of Upper Bavaria. The wedding took place by 14 October 1308. During her marriage, Beatrice gave birth to six children, but only three survived to adulthood:
Matilda -by marriage Margravine of Meissen-,
Louis V the Brandenburger -later Duke of Upper Bavaria, Margrave of
Brandenburg and Count of
Tyrol- and
Stephen II – later Duke of
Lower Bavaria. Duke Louis IV was elected
German King on 20 October 1314. However, another faction had elected
Frederick I of Austria as King on 19 October. The two rival Kings would continue their dispute for the rest of her life. She was one of two rival German queens, with
Isabella of Aragon, wife of Frederick I. Beatrice died, at
Munich, a long time before her husband's coronation as Holy Roman Emperor (in 1328). Two years after her death, Louis IV was remarried to
Margaret II, Countess of Hainaut. ==Issue==