The Klaipėda Region (Lithuanian: Klaipėdos kraštas) or Memel Territory (German: Memelland 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.

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 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.

After the Treaty of Melno was signed, many Lithuanians returned to northeastern Prussia, which became known as Lithuania Minor in the 16th century.

As World War II came to an end in 1945, the Soviet Union incorporated the region into the Lithuanian SSR.

The southern border established by the Treaty of Versailles defines the current international boundary between Lithuania and the Kaliningrad Oblast of the Russian Federation.

[citation needed] The eastern boundaries of Prussia (from 1871, part of the German Empire), having remained unchanged since the Treaty of Melno in 1422, became a matter of discussion following World War I as the newly independent states of Poland and Lithuania emerged.

[3] The division of Prussia was also promoted by Poland's Roman Dmowski[4] in Versailles who acted on the orders of Józef Piłsudski.

[7] As a result of this backlash, Odry left his post shortly after coming to Memel and handed the responsibility of the administration over to High Commissioner Gabriel Jean Petisné.

During the period of French administration, the idea of an independent state of Memelland grew in popularity among local inhabitants.

The organisation Deutsch-Litauischer Heimatbund (German-Lithuanian homeland federation) promoted the idea of a Freistaat Memelland, which later should return to Germany.

On 19 January, the territory was annexed by Lithuania, and the fait accompli was eventually confirmed by the Council of Ambassadors in 1924.

On 8 May 1924, a further Convention on the Klaipėda region confirmed the annexation, and a resulting autonomy agreement was signed in Paris.

In the Lithuanian-German Arbitration and Settlement Agreement (Schieds- und Vergleichsvertrag) of 29 January 1928, the Republic of Lithuania and the Weimar Republic agreed "as a sign of the friendly nature of their relations" to conclude, among other items, a border settlement agreement that included the status of the Memel Territory.

The port reconstruction was certainly one of the larger long-term investment projects enacted by the government of Lithuania in the interwar period.

die evangelische Kirche des Memelgebietes) of 23 July 1925, concluded between the Directorate of the Klaipėda Region and the Evangelical Church of the old-Prussian Union, a church of united administration of Lutheran and Reformed congregations, the mostly Lutheran congregations (and a single Reformed one in Klaipėda) in the Klaipėda Region were disentangled from the old-Prussian Ecclesiastical Province of East Prussia and formed the Regional Synodal Federation of the Memel Territory (Landessynodalverband Memelgebiet) since, being ranked an old-Prussian ecclesiastical province of its own.

At the start of the 1930s, certain leaders and members of pro-Nazi organizations in the region were put on trial by Lithuania "for crimes of terrorism".

The authoritarian regime of Smetona enforced a policy of discrimination and Lithuanisation: it sent administrators from Lithuania, and German teachers, officials, and priests were fired from jobs.

Lithuania introduced a hard-line Lithuanisation campaign that led to even deeper antagonism between local Prussian Lithuanians, Memellanders, Germans and newcomers.

Hitler had anticipated this aboard a Kriegsmarine naval ship and at dawn[26] sailed into Memel to celebrate the return heim ins Reich of the Memelland.

It was under these conditions that the Seimas was forced to approve the treaty, hoping that Germany would not press any other territorial demands upon Lithuania.

The government of the Lithuanian SSR sent agitators into the displaced persons camps to make promises to former inhabitants that they could return and their property would be restored.

Families of notable local Lithuanians, who had opposed German parties before the war, were deported to Siberia.