Lisbon metropolitan area
The Lisbon metropolitan area, centered in the Portuguese capital city of Lisbon, is the largest population concentration in Portugal. The population in 2011 was 2,821,876, of whom 547,733 (19.4%) live in the city of Lisbon. About 26.7% of the total population of Portugal lives in the Lisbon metropolitan area. The area of the Lisbon metropolitan area is 3,015.24 km, which is 3.3% of the total area of Portugal.
Portugal
In 1807, as Napoleon's army closed in on Lisbon, the João VI of Portugal, the Prince Regent, transferred his court to Brazil and established Rio de Janeiro as the capital of the Portuguese Empire. In 1815, Brazil was declared a Kingdom and the Kingdom of Portugal was united with it, forming a pluricontinental State, the United Kingdom of Portugal, Brazil and the Algarves.
As a result of the change in its status and the arrival of the Portuguese royal family, Brazilian administrative, civic, economical, military, educational, and scientific apparatus were expanded and highly modernized. Portuguese and their allied British troops fought against the French Invasion of Portugal and by 1815 the situation in Europe had cooled down sufficiently that João VI would have been able to return safely to Lisbon. However, the King of Portugal remained in Brazil until the Liberal Revolution of 1820, which started in Porto, demanded his return to Lisbon in 1821.