The viticulture of Jerez is practically mono-varietal. 95% of the vines are of the Palomino grape variety, which was brought to the region by Yañez Palomino, a knight in Alfonso X The Wise's court, after the conquest of Jerez in 1264 A.D.
The Pedro Ximenez grape was brought from Germany to the region by Pieter Siemens, a German soldier from the Flanders Regiment. Over time the name "Siemens" was corrupted into "Xímenez".
Finally there's the Moscatel grape, a variety common to both French (Muscat), and Spanish denominations.