During the 19th century, the British Admiralty patrolled the African coast to catch illegal slave traders. The Swedish vessel Diana was intercepted by the British authorities close to the coast of Africa while engaged in carrying slaves from Africa to Saint Bartholomew during this period. The case was taken to court in order to test if the slave trade could be considered contrary to the general law of nations. However, the vessel was returned to the Swedish owners on the ground that Sweden had not prohibited the trade and tolerated it in practice.