Back ارنست الاول دوق برونزويك جروبنهاجن ARZ Ернст I фон Брауншвайг-Грубенхаген Bulgarian Ernst I. (Braunschweig-Grubenhagen) German Ερνέστος Α΄ του Γκρουμπενχάγκεν Greek Ernest I, Duke of Brunswick-Grubenhagen English Ernesto I de Brunswick-Grubenhagen Spanish Ernest Ier de Brunswick-Grubenhagen French Ernesto I di Brunswick-Grubenhagen Italian Ernst I van Brunswijk-Grubenhagen Dutch Ernest I (książę Brunszwiku-Grubenhagen) Polish
Ernst I (u 1297 – 9. märts 1361) oli Grubenhageni vürst.