What is "diermissen"

Diermissen is an old German surname that originated from the " Ostfälisches Altniederdeutsch" dialect spoken by the ancient Saxon tribes, who established in the territory that nowadays we denominate northern Germany. This surname comes from an old family (de Didilmissen) that lived near the modern towns of " Dielmissen" and " Bodenwerder" in modern Lower Saxony (Niedersachsen). Apparently the meaning of this surname is "The house of Thiadhelm" or Thiadelmes-husen, which derives to Didelmissen-Diermissen-Dielmissen. There is evidence of various families around the world and not only in Germany that bear this surname, for example in Costa Rica, United States, Canada, and El Salvador.