List of ministers plenipotentiary of the Austrian Netherlands
In the eighteenth century, it became the norm for the Archduke of Austria, who was lord of the Netherlands by inheritance, to appoint a diplomat with the rank of minister plenipotentiary to represent his interests at the court of the governor-general of the Netherlands in Brussels. The minister plenipotentiary served as an intermediary between the courts of Vienna and Brussels and as a check on the development of any independent policy in the latter.
Source: Wikipedia — List of ministers plenipotentiary of the Austrian Netherlands (CC BY-SA 4.0)