Russo-Turkish War (1877–78): Sofia is liberated from Ottoman rule.

The Russo-Turkish War (1877–1878) was a conflict between the Ottoman Empire and a coalition led by the Russian Empire which included Romania, Serbia, and Montenegro. Precipitating factors included the Russian goals of recovering territorial losses endured during the Crimean War of 1853–1856, re-establishing itself in the Black Sea and supporting the political movement attempting to free Balkan nations from the Ottoman Empire. The Romanian army had around 114,000 soldiers in the war. In Romania the war is called the Russo-Romanian-Turkish War (1877–1878) or the Romanian War of Independence (1877–1878).

Sofia is the capital and largest city of Bulgaria. It is situated in the Sofia Valley at the foot of the Vitosha mountain, in the western part of the country. The city is built west of the Iskar river and has many mineral springs, such as the Sofia Central Mineral Baths. It has a humid continental climate.

The Battle of Sofia was the culmination of Russian General Iosif Gurko's Western Squad for the defeat of the Orhaniye army in the Russo-Turkish War (1877–1878). It led to the Liberation of Sofia from Turkish rule.

The history of Ottoman Bulgaria spans nearly 500 years, beginning in the late 14th century, with the Ottoman conquest of smaller kingdoms from the disintegrating Second Bulgarian Empire. In the late 19th century, Bulgaria was liberated from the Ottoman Empire, and by the early 20th century it was declared independent.

January 4 is the fourth day of the year in the Gregorian calendar; 361 days remain until the end of the year.