Queen Sonja wore Empress Joséphine’s Emerald Tiara. The wife of Napoleon Bonaparte, Empress Joséphine owned a part of the Emeralp Parure of this tiara. Eugene de Beauharnais ( Joséphine's son ) took it to Norway. His daughter Joséphine married to King Oscar I of Sweden. Their great-grand daughter Princess Märtha of Sweden married Crown Prince Olav of Norway in 1929.
Crown Princess Märtha received the tiara as a gift from her parents ( Prince Carl and Princess Ingeborg ) in 1937 for her son's birth ( the current King of Norway Harald V ) Märtha died and never became a Queen of Norway but her daughter-in-law Queen Sonja wears it today.