4 State immunity evolved in close connection to the development of the concept of sovereignty
and the territorial State. It can be traced back to the principle of par in parem non habet
imperium which was mentioned as early as 1354 by Bartolus de Saxoferrato in his Tractatus de
regimine civitatis. It stipulates that a sovereign should not have jurisdiction over another
sovereign.
[...]
22 State immunity entails that a State itself or its property is not subjected to the
proceedings of the court of another State. It does foreclose any proceedings or judgment on the
merits, but does not hinder the service of process and a court decision about the admissibility.
Likewise, it protects the property of a State against any measure taken in relation to the
proceedings.
