A little more info about Dornfelder:

Dornfelder is a relatively recent arrival on the wine grape scene, having been created in 1956 by August Herold as a crossing of Helfensteiner and Heroldrebe. However, since Helfensteiner and Heroldrebe are also crossings, its lineage includes almost every red wine grape grown in Germany. It is especially important in the Rheinhessen and Pfalz regions and is the second most widely planted red grape variety in Germany.