Cartels in the international law of the 17th to the 19th century were a special kind of international treaty. Their purpose was to regulate specific activities of common interest, while the contracting states remained rivals on other fields. Typical for these agreements was that they were to be implemented on an administrative level. Similar to the ‘’cartels’’ for duels and tournaments, these intergovernmental accords represented fairness agreements or gentlemen’s agreements between states. From the [history of the US, intergovernmental cartels are known as the legal basis of humanitarian action. So-called cartel ships were dispatched for missions, such as to carry communications or prisoners between belligerents. From the European history, a broader range of purposes is known. These ‘cartels’ often reflected the cohesion of authoritarian ruling classes against their own unruly citizens. Generally, the European governments concluded - while curbing their mutual rivalries partially - cooperation agreements, which should apply generally or only in case of war:
Deserters, escaped serfs and criminals were to be mutually extradited.
The maintenance of postal and commercial traffic including the entry and exit of couriers should be guarantied in the fields of communication and transport.
‘Customs cartels' and 'coin cartels' were 'regulatory' agreements between Continental-European states in the 19th century.
Against smugglers and counterfeiters, a joint action approach was adopted by the governments contracting on international tradetreaties. The latter often contained the relevant ‘cartel’ regulations in their annexes.
The measures against criminals and unruly citizens were to be conducted regardless of the nationality and origin of the relevant persons. If necessary, national borders could be crossed by police forces of the respective neighboring country for capture and arrest. In the course of the 19th century, the term ‘cartel’ gradually disappeared for intergovernmental agreements under international law. Instead, the term "convention" was used.
