The Wentz/Wantz origins Many of these families have traced their surname origins to original immigrants in the 18th or 19th century from Germany or Switzerland whose last name was Wentz or a variant like Wantz. In their new English-speaking home, the last name sounded like "Vance", and either through regular usage or by the pen of a government official the new spelling stuck.
Several books (see Online Books of Interest) describe the origin of the Wentz surname as a diminutive of "Wenceslaus" or the German variant "Wenzo", and track the name's association with a Saint Wendelin and of course several kings named Wenceslaus, with variants "Wenzelo" from 1198 through "Wenzel" in the 1300s. "Wentz" and "Wenz" were later variants appearing in the 1300s and 1400s near Basel in Switzerland and several locations in Germany. Other sources cite Slavic variants like Vaclav but agree on the same basic timeline.
The stories say an original Wentz family came out of Bohemia (part of the current Czech republic) or Pomerania (now part of Germany and Poland on the south Baltic Sea) and migrated into Bavaria in western Germany and to the city of Basel in Switzerland some 700 years ago. These stories have so far not been verified. In the 1700s and 1800s, however, several German and Swiss Wentz families immigrated to the US where the name became written as Vance.