The Coat of Arms of Nassau has existed since about 1250. There are two versions of the Nassau Arms, representing the two main branches, as a result of two brothers, Count Walram II and Count Otto I, agreeing to divide their father Henry II's lands between them in 1255. The line of Walram added a Crown to the Lion in the Nassau Arms to differentiate it from the Lion used by the line of Otto, although both Lions wear open Crowns nowadays.
The Monarchs of The Netherlands are descendants of Count Otto. The Grand Dukes of Luxembourg are descendants of Count Walram, who also still use the Nassau Quarter in their Arms. Both lines are now extinct in the male line but the Ottovian Line in the form of the Dutch Royal Family (well, some male members of the Royal Family) make use of the Crest as follows:
"On a Helmet, with bars and decoration Or and mantling Azure and Or, issuing from a Coronet Or, a pair of Wings joined Sable each with an arched Bend Argent charged with three Leaves of the Lime-Tree stems upward Vert".
The Crest of the Walram Line is:
"Between two Trunks Azure billetty Or a Lion sejant Or."
The Crest of the Royal House is the Continental style eight demi-arched Royal Crown. The Ottovian Crest is used by Princes as a Family Crest along with that of their respective father as the Royal line was passed through the female line for three generations.
The second Coat of Arms is for the children of Princess Margriet of the Netherlands (Beatrix's sister) and her husband Pieter van Vollenhoven, used by Prince Maurits, Prince Bernhard, Prince Pieter-Christiaan and Prince Floris. This variant also shows two dynastic crests, that of the Ottovian Line of Nassau from their Mother and the blue Wings and silver Star of van Vollenhoven from their Father.