terms.” Alberico Gentili, in his De Jure Belli Libri Tres (1598), drew a distinction between the legitimate occupation of land that was res nullius and illegitimate claims of sovereignty through discovery and occupation of land that was not res nullius, as in the case of the Spanish claim to the Americas. Hugo Grotius, writing in 1625, also stated that discovery does not give a right to sovereignty over inhabited land, “For discovery applies to those things which belong to no one.” By the eighteenth century, however, some writers argued that territorial rights over land could stem from the settlement and cultivation of that land. William Blackstone, in 1756, wrote, “Plantations or colonies, in distant countries, are either such where the lands are claimed by right of occupancy only, by finding them desert and uncultivated, and peopling them from the mother-country; or where, when already cultivated, they have been either gained by conquest, or ceded to us by treaties. And both these rights are founded upon the law of nature, or at least upon that of nations." Borch states that many commentators erroneously interpreted this to mean that uncultivated lands, whether inhabited or not, could be claimed by a colonising state by right of occupancy. Two years after Blackstone, Emer de Vattel, in his Le droit des gents (1758), drew a distinction between land that was effectively occupied and cultivated, and the unsettled and uncultivated land of nomads which was open to colonisation. The Berlin West Africa Conference of 1884-85 endorsed the principle that sovereignty over an unclaimed territory required effective occupation, and that where native populations had established effective occupation their sovereignty could not be unilaterally overturned by a colonising state. The term terra nullius was used in 1885 in relation to the dispute between Spain and the United States over Contoy Island. Herman Eduard von Hoist, wrote, “Contoy was not, in an international sense, a desert, that is an abandoned island and hence terra nullius." In 1888, the Institut de Droit International introduced the concept of territorium nullius (nobody’s territory) as a public law equivalent to the private law concept of res nullius. In 1909, the Italian international jurist Camille Piccioni described the island of Spitzbergen in the Arctic Circle as terra nullius. Even though the island was inhabited by the nationals of several European countries, the inhabitants did not live under any formal sovereignty. In subsequent decades, the