for the new German-Romanian economic agreement which was signed on 10 December 1938, Weinberg wrote that: "Carol made the needed concessions, but he demonstrated his concern for his country's independence by driving a very hard bargain". The British historian D.C. Watt wrote that Carol had a "trump card" in his control of the oil Germany needed so badly and that the Germans were willing to pay a very high price for Romanian oil without which their military could not function. During his summit with Hitler, Carol was much offended when Hitler demanded that Carol free Codreanu and appoint him Prime Minister. Carol believed that as long as Codreanu lived, there was a possible alternative leadership in Romania for Hitler to back, and that if this possibility was eliminated then Hitler would have no choice other than to deal with him. Carol had initially planned to keep Codreanu in prison, but after the terrorist campaign began in October 1938, Carol agreed to Călinescu's plan drawn up in the spring to murder all of the Iron Guard leaders in custody. On the night of 30 November 1938, Carol had Codreanu and 13 other Iron Guard leaders murdered with the official story being that they were "shot while trying to escape". The killings on the night of 30 November 1938 which saw much of the Iron Guard's leadership wiped out have gone down in Romanian history as "the night of the vampires". The Germans were much offended by the murder of Codreanu and for a period in late 1938 waged a violent propaganda campaign against Carol with German newspapers regularly running stories casting doubt about the official version of events that Codreanu had been "shot while trying to escape" while calling Codreanu's murder "a victory for the Jews"Ancel, Jean The History of the Holocaust in Romania, Lincoln: University of Nebraska Press, 2011 page 42. but ultimately economic concerns, especially the German need for Romanian oil caused the Nazis to get over their outrage over the killings of the Iron Guard leaders by early 1939, and relations with Carol soon went back to normal. In December 1938, the National Renaissance Front was formed as the country's only legal party. That same month, Carol appointed his friend since childhood and another member of the camarilla Grigore Gafencu as foreign minister. Gafencu was appointed foreign minister partly because Carol knew he could trust Gafencu and partly