Background
She was a daughter of Gerhard VI of Holstein-Rendsburg and his wife, Catherine Elisabeth of Brunswick-Lüneburg.
Duke of Schleswig duchess of Schleswig
She was a daughter of Gerhard VI of Holstein-Rendsburg and his wife, Catherine Elisabeth of Brunswick-Lüneburg.
Her brother was Adolf VIII/I, Count of Holstein/Duke of Schleswig. On 18 April 1417 Helvig was married to Prince Balthasar of Mecklenburg, who died of the plague in 1421. In 1423 she was married to Dietrich, Count of Oldenburg.
Christian (1426–1481), who succeeded his father as Count of Oldenburg and Delmenhorst.
In 1448, partly because of his mother"s ancestry, he was elected King of Denmark. Adelheid of Oldenburg (1425–1475).
First married Ernest III, Count of Hohenstein (died 1454) and then in 1474 Gerhard VI, Count of Mansfeld (died 1492). Danish royal descent.