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,
Denmark–Sweden border was still a country although under practical control by Germany). The Nordic Passport Union of 1958 removed passport checks at the border. However, custom checks remained in force between Denmark and other Nordic countries until the Schengen acquis of 2001. There was no land border with Denmark before July 2000 when the Øresund Bridge was opened, which had relaxed customs checks from the start. With the European migrant crisis, Sweden re-introduced stricter border controls in November 2015. Since 4 January 2016, Sweden has required carriers to perform identity checks on the Danish side of the Denmark–Sweden border, while still keeping