Their mother Ingeborg had a seat in the guardian government as well as the position of an independent ruler of her own fiefs, and played an important part during their childhood and adolescence.

The marriage was arranged with the terms that Mecklenburg, Saxony, Holstein, Rendsburg and Schleswig would assist Ingeborg in the conquest of Scania.

Euphemia was married in Rostock on April 10, 1336, to her distant kinsman, Albert II, Duke of Mecklenburg (1318 – 2 February 1379), a North-German lord deeply interested in obtaining some power in Scandinavia.

Later the same year, the couple returned to Sweden with Rudolf of Saxony and Henry of Holstein to be present at the coronation of her brother and sister-in-law Blanche of Namur.

In Germany, Euphemia's life as a Duchess consort of Mecklenburg does not appear to have affected her status in Sweden, as she was still a political factor there and her name was still placed on various documents.