Zurich is the largest city in Switzerland and the capital of the canton of Zürich. It is located in north-central Switzerland at the north western tip of Lake Zürich. The municipality has approximately 400,028 inhabitants, the urban agglomeration 1.315 million, and the Zurich metropolitan area 1.83 million. Zürich is a hub for railways, roads, and air traffic. Both Zürich Airport and railway station are the largest and busiest in the country. Permanently settled for around 2000 years, Zürich has a history that goes back to its founding by the Romans, who, in 15 BC, called it Turicum. However, early settlements have been found dating back more than 6400 years ago. During the Middle Ages, Zürich gained the independent and privileged status of imperial immediacy and, in 1519, became a primary centre of the Protestant Reformation in Europe under the leadership of Ulrich Zwingli. The official language of Zürich is (the Swiss variety of Standard) German, but the main spoken language is the local variant of the Alemannic Swiss German dialect.