meant that some English judged them not to be productive users of land. However, Rolston and McVeigh state that Gerald made it clear that Ireland was acquired by conquest and not through the occupation of terra nullius. Rockall According to Ian Mitchell, Rockall was terra nullius until it was claimed by the United Kingdom in 1955. It was formally annexed in 1972. Sealand In 1967, Paddy Roy Bates claimed an abandoned British anti-aircraft gun tower in the North Sea as the "Principality of Sealand". The structure is now within British territorial waters and no country recognises Sealand. Svalbard Denmark–Norway, the Dutch Republic, the Kingdom of Great Britain, and the Kingdom of Scotland all claimed sovereignty over the archipelago of Svalbard in the seventeenth century, but none permanently occupied it. Expeditions from each of these polities visited Svalbard principally during the summer for whaling, with the first two sending a few wintering parties in the 1620s and 1630s. During the 19th century, both Norway and Russia made strong claims to the archipelago. In 1909, Italian jurist Camille Piccioni described Spitzbergen, as it was then known, as terra nullius: The territorial dispute was eventually resolved by the Svalbard Treaty of 9 February 1920 which recognized Norwegian sovereignty over the islands. North America Canada Joseph Trutch, the first Lieutenant Governor of British Columbia, insisted that First Nations had never owned land, and thus their land claims could safely be ignored. It is for this reason that most of British Columbia remains unceded land. In Guerin v. The Queen, a Canadian Supreme Court decision of 1984 on aboriginal rights, the Court stated that the government has a fiduciary duty toward the First Nations of Canada and established aboriginal title to be a sui generis right. Since then there has been a more complicated debate and a general narrowing of the definition of "fiduciary duty". Eastern Greenland Norway occupied and claimed parts of (then uninhabited) eastern Greenland in 1931, claiming that it constituted terra nullius and calling the territory Erik the Red's Land. The Permanent Court of International Justice ruled against the Norwegian claim. The Norwegians accepted the ruling and withdrew their claim. United States A similar concept of "uncultivated land" was employed by John Quincy Adams to identify supposedly unclaimed wilderness. Guano Islands The Guano Islands Act of 18 August 1856 enabled citizens of the U.S. to take possession of islands containing guano deposits.