The Klaipėda Region () or Memel Territory ( or Memelgebiet) was defined by the 1919 Treaty of Versailles in 1920 and refers to the northernmost part of the German province of East Prussia, when as Memelland it was put under the administration of the Entente's Council of Ambassadors. The Memel Territory, together with other areas severed from Germany (the Saar and Danzig) was to remain under the control of the League of Nations until a future day when the people of these regions would be allowed to vote on whether the land would return to Germany or not. Today, the former Memel Territory is controlled by Lithuania as part of Klaipėda and Tauragė counties. Historical overview In 1226 Duke Konrad I of Masovia requested assistance against the Prussians and other Baltic tribes, including the Skalvians who lived along the Neman (Memel) River. In March 1226, Holy Roman Emperor Frederick II issued the Golden Bull of Rimini, which provided that the Teutonic Knights would possess lands taken beyond the Masovian border in exchange for securing Masovia. After uprisings of the Baltic Prussian tribes in 1242 through 1274 failed, the Order conquered many remaining western Balts in Lithuania Minor, including the Skalvians, Nadruvians, and Yotvingians. In 1252 the Order constructed Memel Castle where the Dangė river flows into the Neman, at the north end of the Curonian Spit. In 1422, after centuries of conflict, the Order and the Polish–Lithuanian union signed the Treaty of Melno which defined a border between Prussia and Lithuania. Although Grand Duke Vytautas of Lithuania wanted the border to be coextensive with the Neman River, the treaty border started north of Memelberg and ran southeasterly to the Neman. This border remained until 1918. After the Treaty of Melno was signed, many Lithuanians returned to northeastern Prussia, which became known as Lithuania Minor in the 16th century. After World War I ended in 1918, the Klaipėda Region was defined as a roughly triangular wedge, with the northern border being the Treaty of Melno border, the southern border following the Neman River, and on the west abutting the Baltic Sea. In 1923, fearing that the western powers would create a free state, Lithuanians took control of the region and, as part of larger regional negotiations, incorporated the region into the State of Lithuania. In March 1939 Lithuania acquiesced to Nazi demands and transferred the Klaipėda Region to Germany. As World