Prince Harald (third son of Frederik VIII and Lovisa) and Princess Helena (nee Glücksburg) were married in 1909, and their marriage was the first between the German and the Danish Glücksburg lines.
The marriage was not the best, Helena being a Nazi supporter and over-controlling. She was not liked by many, and the press loved to make fun of her. Harald on the other hand seems to have been popular and respected by the people who knew him.
The couple had five children.
1910-1975 Feodora, Princess of Denmark
1912-1995 Caroline Mathilde, Princess of Denmark
1914-1962 Alexandrine-Louise, Princess of Denmark
1919-1991 Gorm, Prince of Denmark
1923 -1990 Oluf, Count of Rosenborg
The couple in 1909