he had to carefully balance different factions and interests, especially with regards to relations with the Vatican, social reform, and foreign policy. When Southern Italy was liberated by the Allies, he became one of the main representatives of DC in the National Liberation Committee. During the government led by Ivanoe Bonomi, De Gasperi was appointed minister without portfolio and, in Ferruccio Parri's cabinet, he became minister of foreign affairs. Prime Minister of Italy From 1945 to 1953, he was the prime minister of eight successive DC-led governments. His eight-year rule remains a landmark of political longevity for one leader in modern Italian politics. During his successive governments, Italy became a republic (1946), signed a peace treaty with the Allies (1947), joined the NATO in 1949 and became an ally of the United States, which helped to revive the Italian economy through the Marshall Plan. During that time, Italy became a member of the European Coal and Steel Community (ECSC), which later evolved into the European Union (EU). In December 1945, he became prime minister for the first time, succeeding Ferruccio Parri and leading a coalition government that included both Italian Communist Party (PCI) and Italian Socialist Party (PSI), along with other minor parties like Italian Republican Party (PRI), Italian Liberal Party (PLI) and Action Party (PdA). Communist leader Palmiro Togliatti acted as deputy prime minister. He tried to soften the terms of the pending Allied peace treaty with Italy and secured financial and economic aid through the European Recovery Program (Marshall Plan) – which was opposed by the Communists. In June 1946, a constitutional referendum to decide whether Italy would remain a monarchy or become a republic resulted in 54% of the vote favouring a republic. De Gasperi served as provisional head of state until the Constituent Assembly elected Liberal politician Enrico De Nicola provisional head of state on 28 June 1946. As chief of the Italian delegation at the World War II peace conference in Paris, De Gasperi harshly criticized the sanctions imposed on Italy, but obtained concessions from the Allies that guaranteed Italian sovereignty. Under the Treaty of Peace with Italy, 1947, the eastern border area was lost to Yugoslavia and the free territory of Trieste was divided between the two states. One of his most striking achievements in foreign policy was the Gruber-De Gasperi Agreement with Austria in September 1946, that established his home region, South Tyrol,