The preamble to the treaty states that the King of Spain "concurs in the fullest manner, in the sentiments of his Britannic Majesty, with respect to the injustice and inhumanity of the traffic in slaves [...] and engages moreover to prohibit His subjects from carrying on the Slave Trade". The King is "resolved to co-operate with His Britannic Majesty in the cause of humanity". It is resolved that Spanish ships will no longer be permitted to purchase or trade in slaves on the coast of Africa north of the Equator after 30 May 1820, and that in exchange Britain will pay £400,000 to the king of Spain "as a full compensation for all losses sustained by the subjects of His Catholic Majesty". The mutual right of visit by naval cruisers and the establishment of Mixed Commission courts were also agreed in this treaty.