German sailors of the Kriegsmarine (War Navy) march through the streets of Memel, recently retaken from Lithuania. Following World War I and the signing of the Treaty of Versailles, Germany lost control of Memel and the surrounding area and the city was made a protectorate of the Entente States. The French became provisional administrators of the region until a more permanent solution could be worked out. Both Lithuania and Poland campaigned for their rights in the region. Not waiting for an unfavorable decision, the Lithuanians decided to stage the Klaipėda Revolt in January 1923, overtaking Memel Territory and renaming the city Klaipėda. As tensions in pre-war Europe continued to grow in the late 1930s, the Lithuanian government feared Germany would make a tactical move against Lithuania to reacquire the region. German Foreign Minister Joachim von Ribbentrop delivered an ultimatum to Lithuanian Foreign Minister Juozas Urbšys on 20 March 1939, demanding the surrender of Klaipėda. The ultimatum was issued just five days after the German occupation of Czechoslovakia. Lithuania, unable to secure international support for its cause, submitted to the ultimatum and ceded the disputed region to Germany in the late evening of 22 March 1939. Memel, East Prussia, Germany (now, Klaipėda, Klaipėda County, Lithuania). 23 March 1939.