The House of Arenberg is an aristocratic lineage that is constituted by three successive families that took their name from Arenberg, a small territory of the Holy Roman Empire in the Eifel region. The inheritance of the House of Croÿ-Aarschot made the Arenbergs the wealthiest and most influential noble family of the Habsburg Netherlands. The family's Duchy of Arenberg was mediatized in 1810. As such, the Arenbergs belong to the small group of families that constitute the Hochadel.

The House of Ligne is one of the oldest Belgian noble families, dating back to the eleventh century. The family's name comes from the village of Ligne where it originated, between Ath and Tournai in what is now the Hainaut province of Belgium.