The Eichsfeld (English: Oaksfield) is a historical region in the southeast of Lower Saxony (which is called "Untereichsfeld" = lower Eichsfeld) and northwest of Thuringia ("Obereichsfeld" = upper Eichsfeld) in the south of the Harz mountains. Until 1803 the Eichsfeld was for centuries part of the Archbishopric of Mainz, which is the cause of its current position as a Catholic enclave in the predominantly Protestant north of Germany. Following German partition in 1945, the West German portion became Landkreis Duderstadt. A few small transfers of territory between the American and Soviet zones of occupation took place in accordance with the Wanfried Agreement.