At the time of Yalta over 200,000 troops of the Polish Armed Forces in the West were serving under the high command of the British Army. Many of these men and women were originally from the Kresy region of eastern Poland including cities such as Lwów and Wilno. They had been deported from Kresy to the Soviet gulags when Hitler and Stalin occupied Poland in 1939 in accordance with the Nazi–Soviet Pact. Two years later, when Churchill and Stalin formed an alliance against Hitler, the Kresy Poles were released from the Gulags in Siberia, formed the Anders Army, and marched to Iran to create the II Corps (Poland) under British high command. These Polish troops contributed to the Allied defeat of the Germans in North Africa and Italy, and hoped to return to Kresy in an independent and democratic Poland at the end of the War. But at Yalta, the borders agreed in Tehran in 1943 were finalized meaning that Stalin would keep the Soviet gains Hitler agreed to in the Nazi–Soviet Pact, including Kresy, and carry out Polish population transfers. These transfers included to the land Poland gained at Tehran in the West, at the expense of Germany. Consequently, at Yalta, it was agreed that tens of thousands of veteran Polish troops under British command should lose their Kresy homes to the Soviet Union. In reaction, thirty officers and men from the II Corps committed suicide.