What is "gerdes"

Gerdes , or Geerdes, is a surname of German origin. It is a patronymic name, i.e. it comes from "son of Gerhard". When around 1800 the Prussian government under French occupation decided to fix the surnames, the contemporary "son of Gerhard" had to keep his name. In Ostfriesland, the law was ignored until at least 1811.