The flag of Bulgaria (Bulgarian: знаме на България,) is a tricolour consisting of three equal-sized horizontal bands of (from top to bottom) white, green, and red. The flag was first adopted after the Russo-Turkish War (1877–1878), where Bulgaria gained independence. The national flag at times was charged with the state emblem, especially during the People's Republic of Bulgaria. The current flag was re-established with the 1991 Constitution of Bulgaria and was confirmed in a 1998 law.
From 1948 until 1990 the emblem of People's Republic of Bulgaria was placed on the left side of the white stripe. It contained a lion within a wreath of wheat ears below a red five-pointed star and above a ribbon bearing the years 681, the year of the establishment of the First Bulgarian Empire by Asparukh and 1944, the year when the Fatherland Front took power which lead to the establishment of the People's Republic of Bulgaria.
The new Constitution of Bulgaria, adopted in 1991, describes the Bulgarian flag as follows: “ Art. 166. The flag of the Republic of Bulgaria shall be a tricolour: white, green, and red from top, placed horizontally.source: wikipedia