"The history of this autochthonous grape variety, which is over 8,000 years old, brings us to the origins of the cultivated grape. It is the real "Blue Silvaner". It is THE regular variety in the group of the "Blue Schirvaner". Shirvan is an ancient wine region on the Caspian Sea, home to a number of historical grape varieties. The "black gemstone" was exported over the Carpathian Mountains to Franconia and the Taubertal as early as the Middle Ages. The relative of today's Pinot Noir was thought to be extinct until 2007." (https://historische-rebsorten.de/rebsorte/suessschwarz/)