Tallinn is the capital city and main seaport of Estonia. It is situated on the southern coast of the Gulf of Finland, in north central Estonia., 80 kilometres south of Helsinki. Tallinn's population is registered at 399,180 (as of November 2006). In 1154 Tallinn was marked on the world map of the Arab cartographer al-Idrisi.
As an important port for trade between Russia and Scandinavia, it became a target for the expansion of the Teutonic Knights and Kingdom of Denmark during the period of Northern Crusades in the beginning of the 13th century when Christianity was forcibly imposed on the local population. Danish rule of Tallinn and Northern Estonia started in 1219. According to Eurostat, the statistical agency of the European Union, of all EU member states' capital cities, Tallinn has the largest number of non-EU nationals: 27.8% of its population are not EU citizens.