Virtually unknown in the UK, the domra is a Russian/Ukrainian instrument originating from the 16th Century

Not to be confused with the Turkish dombra, it is a long-necked folk string instrument of the lute family with a round body and three or four metal strings. Ukrainian domras have 4 strings are tuned to G-D-A-E, the same as a mandolin or violin, and has a very similar note range to both. The thin neck has metal frets and is strung with steel strings.

After gaining popularity in the 16th and 17th centuries, domras rapidly fell out of favour after Tsar Alexis of Russia ordered the persecution of Russian folk musicians. After a period of time they were supplanted by balalaikas, a three-stringed instrument with a triangular body as they were simpler to play.

They were revived in 1896 when a broken instrument was discovered in a rural stable and recreated. And 10 years later a 4-stringed version was created by a Moscow instrument maker.

See more at Wikipedia.