Maria I of Portugal forced Portugal to cede Olivença and other border towns to Spain. (This cession is not recognized by the present Portuguese government, and the country officially considers those territories still to be Portuguese possessions.) On September 29, 1801 John VI signed the Treaty of Madrid (1801), ceding half of Guyana to France, which became French Guiana. The refusal of the Portuguese government to join the French-sponsored Continental Blockade against Britain culminated in the late 1807 Franco-Spanish invasion of Portugal led by General Junot. The ultimate Napoleonic plan for Portugal was to split it into three sections. The northern parts of Portugal,
Norway–Russia border do not travel outside a zone from the border. Negotiations on the outside marine border were initiated in 1970. Norway claimed, in accordance with the United Nations Convention on the Law of the Sea Article 15 and the Convention on the High Seas, that the border should follow the equidistance principle, the border being defined by midpoints between the nearest land area or islands, as is normal practice internationally. The Soviet Union claimed, based on a decision by Joseph Stalin from 1926, which was not recognized by any other country than the Soviet Union, that a "sector principle" should apply,