One of Europe's oldest countries, the Kingdom of Bulgaria was established in 681 when the Bulgars, a tribe from Asia, moved in and merged with the local populations.
A significant European power by the 9th century, Bulgaria was overrun by the Ottoman Empire at the end of the 14th century. By 1908, Bulgaria was a fully independent kingdom again. The country fought on the losing side in both world wars. It is important to note that Bulgaria refused to comply with Germany's 1943 resolution to deport all Jews to Auschwitz, instead protecting the 50,000 Jewish members of the community.
After WWII, Bulgaria fell into the Soviet camp, where it remained until 1990 when multi-party elections were held. Bulgaria became a member of NATO in 2004, and joined the European Union in 2007.
Bulgaria on Wikipedia