His/Her Ducal Serene Highness (abbreviation: HDSH) was a style used by members of certain ducal families, such as those of Nassau, Braganza, and the Ernestine duchies (until 1844).
The title "His/Her Ducal Serene Highness" (HDSH) was a formal designation used for members of specific ducal families, including those from Nassau, Braganza, and the Ernestine duchies until 1844.