Dorothea of Brandenburg

Dorothea of Brandenburg (31 December 1430 – 10 November 1495) was Queen of Denmark, Norway, and Sweden under the Kalmar Union as the consort of first Christopher III of Denmark and later Christian I of Denmark. She served as interim regent during the interregnum in 1448 and as regent in the absence of her second husband during his reign. She and Christian had three surviving children: John, Margaret, and Frederick, of whom John served as king of the union and both sons served as kings of Denmark and Norway.

Source: Wikipedia — https://en.wikipedia.org/wiki/Dorothea_of_Brandenburg