Plautdietsch, or Mennonite Low German, was originally a Low Prussian variety of East Low German, with Dutch influence, that developed in the 16th and 17th centuries in the Vistula delta area of Royal Prussia. The word is the form, in that language, of Plattdeutsch (Low German). Plaut is the same word as German platt or Dutch plat, meaning 'flat' or 'low' (referring to the plains of northern Germany), and the name Dietsch corresponds etymologically to Dutch Duits and German Deutsch (both meaning "of the Tribe" i.e."German"), which originally meant 'vernacular language' in all the continental West Germanic languages.