Until the 20th century, the lands of modern day Belarus belonged to several countries, including the Principality of Polotsk, the Grand Duchy of Lithuania, the Polish � Lithuanian Commonwealth, and the Russian Empire. As a result of the Russian Revolution, Belarus became a founding constituent republic of the Soviet Union and was renamed as the Byelorussian Soviet Socialist Republic. The borders of Belarus took their modern shape in 1939 when lands that were part of the Second Polish Republic were incorporated into after the Soviet invasion of Poland. The nation and its territory were devastated in World War II, during which Belarus lost about a third of its population and more than half of its economic resources. The republic was redeveloped in the post-war years. In 1945 the Belorussian SSR became a founding member of the UN, along with the Soviet Union and the Ukrainian SSR.
The parliament of the republic declared the sovereignty of Belarus on 27 July 1990, and during the dissolution of the Soviet Union, Belarus declared independence on 25 August 1991. Alexander Lukashenko has been the country's president since 1994. Under his lead and despite objections from Western governments, Soviet-era policies, such as state ownership of the economy have been continued. According to some organizations and countries, elections have been unfair, and political opponents have been violently suppressed. In 2000, Belarus and Russia signed a treaty for greater cooperation, with some hints of forming a Union State.
Most of Belarus's population of 9.49 million reside in the urban areas surrounding Minsk and other oblast (regional) capitals. More than 80% of the population are native Belarusians, with sizable minorities of Russians, Poles and Ukrainians. Since a referendum in 1995, the country has had two official languages: Belarusian and Russian. The Constitution of Belarus does not declare an official religion, although the primary religion in the country is Russian Orthodox Christianity. The second most popular, Roman Catholicism, has a much smaller following by comparison, but both Orthodox and Catholic Christmas and Easter are officially celebrated as national holidays. Belarus also has the highest Human Development Index among members of the Commonwealth of Independent States.