Bulgaria marks on March 3 its National Holiday, the anniversary of its liberation from Ottoman rule.

138 years ago, in a tiny town near Istanbul named San Stefano, a peace treaty was signed bringing Bulgaria back to the political map.

The treaty was a result of the Russo-Turkish War of 1877-1878, known in Bulgaria as the Liberation War. Russia moved to declare war on the Ottoman Empire in the spring of 1877 using as an occasion the atrocities against the Bulgarian population during the April Uprising of 1876.

At the time, both the United States and Europe were able to read about the April Uprising events described by US journalist Januarius MacGahan, working for British newspapers (MacGahan's grave in his hometown in New Lexington, Ohio, identifies him as "the Liberator of Bulgaria).

The holiday will be honored with ceremonies, traditionally held throughout the country, and particularly solemn in towns and cities boasting victorious battles of Russian soldiers and Bulgarian volunteers in the 1877-1878 Liberation War.

Some 66 000 Russian, Belorussian, Ukrainian, Finnish, and Romanian soldiers were killed and about 140 000 were wounded while fighting against the Ottomans. About 30 000 Bulgarians were slaughtered by Ottoman troops and irregulars during the fighting.

However, the San Stefano Treaty was not final and its clauses were revised at the Congress of Berlin, which took place a couple of months later in 1878. It ended with the redistribution back to the Ottoman Empire of certain Bulgarian-populated territories that the previous treaty had given to the Principality of Bulgaria, most notably Macedonia.

The Congress of Berlin (June 13 - July 13, 1878) was a meeting of the European Great Powers' and the Ottoman Empire's leading statesmen. In the wake of the Russian-Turkish War, 1877-78, the meeting's aim was to reorganize the countries of the Balkans.

Otto von Bismarck, who led the Congress, undertook to balance the distinct interests of Britain, Russia and Austria-Hungary. The congress was aimed at the revision of the Treaty of San Stefano and at keeping Constantinople in Ottoman hands.

March 3 was honored for the first time in 1880, on the occasion of the Enthronement of Russian Emperor Alexander the Second. Since 1888, March 3 has become Bulgaria's Day of Liberation, but it was not declared National Holiday until 1978.

With a Parliamentary Decree from 1990, March 3 was included in the list of Bulgaria's official holidays.

Liberation Day has been leaving Bulgarians divided in the past years, with some historians claiming it creates a state where Russia has the final say and over which the Ottoman Empire still wields influence. These have suggested that the Unification or Independence Day. Their opponents, on the other hand, argue March 03 reinstated Bulgaria's statehood and should therefore be respected.

Regardless of these disputes, the liberation put an end to hundreds of years of Ottoman rule which began in the late 14th century.

This Thursday, visits to a number of museums and galleries across the country will be free of charge.

In the capital Sofia, these include the National History Museum, the National Museum of Military History, the Sofia City Art Gallery, the Sofia History Museum, the Sofia Zoo and the Vrana compound.

Elsewhere, free entry will also be offered by the Aviation Museum of Plovdiv; the Naval Museum of Varna; the Regional History Museums of Blagoevgrad, Vratsa, Burgas, Veliko Tarnovo, Pleven, Shumen, Haskovo, Plovdiv, and Stara Zagora; the History Museum of Botevgrad; the History Museum and Art Gallery of Kazanlak; the Abritus Museum and Stanka and Nikola Ikonomovi house in Razgrad.