Thanks so much for your support! I personally don't know when it was written. It is often not easy to recover the history of such music because of it's oral tradition as common with folk music. This is a transcription someone made of it. Perhaps finkenchris can provide us some more information here? :) He was actually the one who came up with the idea for this special piece fo music:)
RE: STEEMIT OPEN MIC WEEK 45: Bulgarian Folk in 7/8 Beat by senzenfrenz (cello) & finkenchris (violin)