William III of England | George III of the United Kingdom | Henry III of England | George III | Edward III of England | Istria | Henry III | Edward III | Engelbert Humperdinck | Charles III of Spain | William III | Loudon Wainwright III | WTA Tier III tournaments | Richard III of England | Engelbert Humperdinck (singer) | Benigno Aquino III | Pope Alexander III | Star Wars Episode III: Revenge of the Sith | Henry III of France | Gustav III of Sweden | Shalmaneser III | Alexander III of Russia | Albatros D.III | Frederick III | Rainier III, Prince of Monaco | Otto III | Frederick William III of Prussia | Victor Emmanuel III of Italy | III | Frederick III, German Emperor |
Bernhard's paternal grandparents were Margrave Engelbert III of Istria and Matilda of Sulzbach.
The known siblings of Gertrude include (1) Gebhard III, Count of Sulzbach, (2) Adelheid, Abbess of Niedernburg at Passau, (3) Bertha of Sulzbach, Byzantine Empress, (4) Luitgarde, wife first of Godfrey II of Leuven and secondly of Hugo XII, Count of Dagsburg and Metz, and (5) Matilda of Sulzbach, wife of Engelbert III of Istria.