the announcement on the radio to the rest of the country. Five days later, a crowd of 200,000 (according to the press) rallied in the zócalo in support of Cárdenas's action. On April 12, 1938, a crowd of thousands of all classes gathered in front of the Palacio de Bellas Artes to make donations to pay the debt to foreign companies. Donations varied from chickens to jewelry. (see photo). On June 7, 1938, President Cárdenas issued a decree creating Petróleos Mexicanos (PEMEX), with exclusive rights over exploration, extraction, refining, and commercialization of oil in Mexico. On June 20, PEMEX started operations. Opposition International In retaliation, the oil companies initiated a public relations campaign against Mexico, urging people to stop buying Mexican goods and lobbying to embargo U.S. technology to Mexico. Many foreign governments closed their markets to Mexican oil, hoping that PEMEX would drown in its own oil. However, the U.S. government of Franklin Delano Roosevelt had issued the Good Neighbor Policy, aiming to recalibrate U.S.-Latin American relations; the U.S. government did not intervene to aid U.S. oil companies affected by the Mexican expropriation. Mexican finances suffered due to the boycott, the Mexican peso was devalued, and an immediate 20% increase in prices was suffered by the Mexican population. In a trip to New York to negotiate with oil companies, Mexican treasury minister, Suarez, serendipitously met an American intermediate, William Rhodes Davis from Davis Oil Company, who had a refinery in Europe, and asked for a collaboration. Davis mediated between Mexico and Germany to a barter agreement where Mexico would give crude oil to Davis, who then would provide refined oil products to Germany in exchange for machinery to Mexico. By 1940, Mexico had an agreement with the American Sinclair Oil Corporation to sell crude oil to the U.S, and the full-scale war in Europe guaranteed that Mexican oil would have international customers. PEMEX developed into one of the largest oil companies in the world and helped Mexico become the world's seventh-largest oil exporter. Domestic Saturnino Cedillo, a cacique from San Luis Potosí and former Secretary of Agriculture, showed the strongest opposition to Cárdenas's measures. Cedillo had in the past supported Cárdenas in a conflict with ex-President Plutarco Elías Calles, but disagreed with his plan of reforms. On May 15 of the same year, the state congress of San Luis Potosí issued a decree where it refused to recognize Cárdenas