Minister who was appointed mediator put the matter into abeyance to allow the contending parties to attempt to resolve the dispute. Ironically, Reza Shah who had stood firm in demanding the abolishment of the D'Arcy concession, suddenly acquiesced to British demands, much to the chagrin and disappointment of his Cabinet. A new agreement with the Anglo-Persian Oil Company was agreed to after Cadman visited Iran in April 1933 and was granted a private audience with the Shah. A new agreement was ratified by the National Consultative Assembly on May 28, 1933, and received Royal assent the following day. 1933 agreement According to Daniel Yergin, "By the end of April 1933, a new agreement was finally forged. The concession area was reduced by three-quarters. Persia was guaranteed a fixed royalty of four shillings per ton, which protected it against fluctuations in oil prices. At the same time, it would receive 20 percent of the company's worldwide profits that were actually distributed to shareholders above a certain minimum sum. In addition, a minimum annual payment of £750,000, irrespective of other developments, was guaranteed. The royalties for 1931 and 1932 were to be recalculated on the new basis, and the 'Persianization' of the workforce was to be accelerated. Meanwhile, the duration of the concession was extended from 1961 to 1993." By 1950, Abadan had become the world's largest refinery. The Anglo-Persian Oil Company continued its large Persian operations although it changed its name to the AIOC in 1935. In spite of diversification the AIOC still relied heavily on its Iranian oil fields for three-quarters of its supplies, and controlled all oil in Iran. Nationalisation and coup Discontent in Iran Under the 1933 agreement with Reza Shah, the AIOC promised to give laborers better pay, more chances for advancement, build schools, hospitals, roads and a telephone system. AIOC did not fulfill these promises. In August 1941, the Allied powers Britain and the Soviet Union invaded and occupied Iran in order to secure the oilfields and open a secure supply route to the USSR. The Persian Corridor sent over 4 million tonnes of American Lend-Lease and other materiel alone. Reza Shah was forced to abdicate in favor of his young son who they perceived would be far less able to act against their interests. Following World War II, nationalistic sentiments were on the rise in the Middle East, the most notable example being Iranian nationalism.