Helvig of Schauenburg

Helvig of Schauenburg (1398–1436), also known as Hedwig of Schauenburg, was a duchess of Schleswig and a countess of Holstein from the family of Schauenburg, and ancestor of the Danish Royal houses of Oldenburg and Schleswig-Holstein-Sonderburg-Glücksburg.

She was a daughter of Count 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. Through their father, Helvig and Adolf were Cognatic descendants of the King Eric V of Denmark.

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 Count Dietrich of Oldenburg. From her second marriage she had the following issue:

• 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. He also inherited the counties of Schleswig and Holstein upon the death of his childless uncle, Adolf VIII.
• Maurice (1428–1464); when his elder brother became king, he was given the County of Delmenhorst.
• Gerhard (1430–1500); when his eldest brother had become king, he was given the county of Oldenburg, and from his other brother's heirs he also inherited Delmenhorst in about 1483.
• Adelheid (1425–1475), first married count Ernest III of Hohnstein (died 1454) and then in 1474 Count Gerhard VI of Mansfeld (died 1492).