The Nassau's themselves can be traced back to the 11th century, so that's a win for Stephanie:
House of Nassau - Wikipedia, the free encyclopedia
I am reading a biography of William of Orange at the moment and also in his times the Lannoy family seems to belong to the top 10 of the Burgundian Netherlands, on the same level as the Ligne's, Croy's, Lalaings, Nassaus, Arenbergs, Egmonts, Barleymonts, Horne's etc. The family also supplied several stadholders:
Hugo van Lannoy, Stadholder of Holland & Zeeland 1433-1440.
Jan III van Lannoy, stadholder of Holland & Zeeland 1448-1462.
Ferdinand van Lannoy, stadholder of Atresia 1571-1578