Lisbon is the capital and the largest city of Portugal, with a population of 552,700 It is continental Europes westernmost capital city and the only one along the Atlantic coast. Lisbon lies in the western Iberian Peninsula on the Atlantic Ocean and the River Tagus. The westernmost areas of its metro area is the westernmost point of Continental Europe. Lisbon is recognised as a global city because of its importance in finance, commerce, media, entertainment, arts, international trade, education and tourism. It is also the political centre of the country, as its seat of Government and residence of the Head of State. Lisbon is one of the oldest cities in the world, and the oldest in Western Europe, predating other modern European capitals such as London, Paris and Rome by centuries. Julius Caesar made it a municipium called Felicitas Julia, adding to the name Olissipo. Ruled by a series of Germanic tribes from the 5th century, it was captured by the Moors in the 8th century. In 1147, the Crusaders under Afonso Henriques reconquered the city and since then it has been a major political, economic and cultural centre of Portugal. Unlike most capital cities, Lisbons status as the capital of Portugal has never been granted or confirmed officially – by statute or in written form. Its position as the capital has formed through constitutional convention, making its position as de facto capital a part of the Constitution of Portugal. Lisbon enjoys a Mediterranean climate. It has one of the warmest winters of any metropolis in Europe, with average temperatures during the day and at night from December to February. The typical summer season lasts about four months, from June to September, although also in April temperatures sometimes reach around .