httpv://www.youtube.com/watch?v=5bpcDe7mEXM
From the video author:
My new keyed fiddle (“Schlüsselfiedel” in German, “nyckelharpa” in Swedish). This instrument was common throughout the German speaking areas until the 17th century – from then on, it was kept only in the area of Uppland in Sweden, where the art of the instrument was rediscovered in the 20th century.
Unlike modern Swedish nyckelharpor, this instrument has only one row of keys and two drone strings. The melody string is tuned in a’, the drones in a and e’.
The tune is a 16th century dance from Austria/Germany.