This is highly unusual in the Netherlands, where such a cloak is normally reserved for nobility, the pope and national coats of arms.
This seal dates from 1322 and it shows not three but four fleur de lye standing on top of a shield.
In 1601 a seal was used showing four lions with underneath waves on top of a label and three fleur de lis in the chief.
The first by the High Councill of Nobility recorded blazon was: An escutcheon gules, charged with three golden lilies, standing 2 and 1; the lower with 4 lions of gold.
The escutcheon is placed on a support of natural wood colour and held by two naked boys, they hold up on both sides a white lined and bordered with gold fringe mantle with baldachin azure.The blazon was changed on 24 Octobre 1936, but the actual coat of arms wasn't changed.