By late 1938, Lithuania had lost control over the situation in the Memel Territory. In the early hours of 23 March 1939, after a political ultimatum caused a Lithuanian delegation to travel to Berlin, the Lithuanian Minister of Foreign Affairs Juozas Urbšys and his German counterpart Joachim von Ribbentrop signed the Treaty of the Cession of the Memel Territory to Germany in exchange for a Lithuanian Free Zone in the port of Memel, using the facilities erected in previous years.