History : When London offered Gibraltar to Madrid exchanging it with a Moroccan territory

Even though the Moroccan State has toned down the territorial dispute over the possession of Gibraltar, the Kingdom was at the center of almost all the political solutions surrounding the Spanish-British disagreement over the control of the overseas territory. This was confirmed later through a letter that was sent in July 1940. 

Moroccan diplomats #5 : Mohamed Zebdi, Sultan Hassan I’s ambassador to the European powers

Sent in 1876 by Sultan Hassan I to Europe, Ambassador Mohamed Zebdi met during his trip the French president, Queen Victoria, and the King of Italy.