Romanian Bridgehead The Romanian Bridgehead ( ) was an area in southeastern Poland , now located in Ukraine . During the Invasion of Poland of 1939 ( at the start of World War II ) , on September 14 the Polish Commander in Chief Marshal of Poland Edward Rydz - Śmigły ordered all Polish troops fighting east of the Vistula ( approximately 20 divisions still retaining cohesion ) to withdraw towards Lwów , and then to the hills along the borders with Romania and the Soviet Union . The plan was a fall back plan in case it was impossible to defend the Polish borders , and assumed that the Polish forces would be able to retreat to the area , organise a successful defence until the winter , and hold out until the promised French offensive on the Western Front started . Rydz - Śmigły predicted that the rough terrain , the Stryj and Dniestr rivers , valleys , hills and swamps would provide natural lines of defence against the German advance . The area was also home to many ammunition dump s that were prepared for the third wave of Polish troops , and was linked to the Romanian port of Constanţa , which could be used to resupply the Polish troops . This plan is one of the reasons the Polish - Romanian Alliance was not activated by Poland . Poland and Romania had been allied since 1921 and the defensive pact was still valid in 1939 . However , the Polish government decided that it would be much more helpful to have a safe haven in Romania and a safe port of Constanţa that could accept as many Allied merchant ships as required to keep Poland fighting . The Polish Navy and merchant marine were mostly evacuated prior to September 1 ( see Peking Plan ) ; they were to operate from French and British ports and deliver the supplies through Romania . The Soviet Union invaded from the east in early hours of September 17 , breaking the the non - aggression pact with Poland , while French , despite their promises , had taken no significant offensive against Germany , making it impossible for the Polish army to hold out at least in eastern parts of the country . In the late hours of that day , the Polish government and members of the military high command crossed the Polish - Romanian border with intention to move to France where the Polish forces in the West were being formed . Polish units were ordered to evacuate Poland and reorganize in France . Up to 120 , 000 Polish troops withdrew through the Romanian Bridgehead area to neutral Romania and Hungary . The majority of those troops joined the newly formed Polish Armed Forces in the West in France and the United Kingdom in 1939 and 1940 . Until the United States entered the war and Germany attacked the Soviet Union ( " Operation Barbarossa " ) , the Polish army was one of the largest forces of the Allies . The Romanian government also received the treasury of the National Bank of Poland in 1939 . One part of it , consisting of 1 , 261 crates containing 82 , 403 kg of gold , was loaded aboard a commercial ship in the port of Constanţa , and transported to Western Europe . The transport was escorted by ships from the Romanian Navy , in order to prevent an interception by Soviet submarine s in the Black Sea . The second part of the treasury was deposited in the Romanian National Bank . It was returned to Poland on September 17 , 1947 . A fictional portrayal of the gold ' s evacuation from Warsaw forms part of the novel " The Polish Officer " , by Alan Furst .