The Brunonids (or Brunonians, German: Brunonen, Latin: Brunones, i.e. "Brunos") were a Saxon noble family in the 10th and 11th centuries, who owned property in Eastphalia (around Brunswick) and Frisia.
The town of Brunswick, located at the western edge of the Derlingau, became their comital seat in the 9th or 10th century; according to legends, Brunswick (the name literally means "Brun's town") was founded by one of the Brunonids named Brun — it is unclear by which one.
Egbert II's sister, Gertrude of Brunswick, had a daughter with her second husband, Henry the Fat, Margrave of Frisia of Northeim.
This daughter, Richenza (d. 1141) married Lothar of Süpplingenburg, who was Duke of Saxony and later became Holy Roman Emperor.
Their daughter Gertrude (d. 1143) married Duke Henry the Proud of Saxony and Bavaria, a member of the House of Welf.