The appellation Alsace Grand Cru was first defined as a single, if sometimes controversial, appellation in 1975 when Schlossberg was the prototype. The wine had to come from a single named vineyard site, or lieu-dit, a single vintage, and (initially) be made from just one of four permitted varieties, Riesling, Muscat, Gewurztraminer, or Pinot Gris. By 1983 there were 26 lieux-dits, then 50 by 1992. Varietal exceptions have been allowed such as the blend allowed, under pressure from Deiss, in Altenberg de Bergheim, and the estimable Sylvaner of Zotzenberg. In 2007 Kaefferkopf became the 51st lieu-dit to be awarded AOC Alsace Grand Cru status and blends based on a majority of Gewurztraminer were permitted in addition to the four varietals. Four years later the umbrella Alsace Grand Cru AOC was divided into 51 individual AOC Alsace Grands Crus appellations, which affords each lieu-dit AOP-level guarantees of quality.