Estonia was settled near the end of the last glacial era, beginning from around 8500 BC. Before the German invasions in the 13th century proto-Estonians of the Ancient Estonia worshipped the spirits of nature.[citation needed] Since the Northern Crusades Estonia became a battleground for centuries where Denmark, Germany, Russia, Sweden and Poland fought their many wars over controlling the important geographical position of the country as a gateway between East and West.
Being conquered by Danes and Germans in 1227, Estonia was ruled initially by Denmark in the north, by the Livonian Order, an autonomous part of the Monastic state of the Teutonic Knights and Baltic German ecclesiastical states of the Holy Roman Empire. From 1418–1562 the whole of Estonia was part of the Livonian Confederation. After the Livonian War, Estonia became part of the Swedish Empire from the 16th century to 1710/1721, when it was ceded to the Russian Empire as the result of the Great Northern War. Throughout this period the Baltic German nobility enjoyed autonomy, where the language of administration and education was German.
The Estophile Enlightenment Period 1750–1840 led to the Estonian national awakening in the middle of the 19th century. In 1918 the Estonian Declaration of Independence was issued. The Estonian War of Independence ensued on two fronts between the newly-proclaimed state and Bolshevist Russia to the east and the forces of the United Baltic Duchy (the Baltische Landeswehr) to the south, resulting in the Tartu Peace Treaty recognising Estonian independence in perpetuity. Prior to the Second World War, Estonia was occupied and according to the USA,the EU, and the European Court of Human Rights  illegally annexed by the Soviet Union as a result of the Molotov–Ribbentrop Pact. During the war Estonia was occupied by Nazi Germany, then reoccupied by the Soviet Union in 1944. Estonia regained independence in 1991 after the collapse of the USSR and joined the European Union in 2004.