The king, Reza Shah, developed his country and called in foreign technicians to help. These included engineers from the UK and countries in Europe. The UK controlled much of the oil development through the company Anglo-Iranian Oil.
In 1941, the UK wanted Iran to expel technicians from Germany as the two countries were at war. Iran refused as it had declared itself neutral. The UK and Russia disregarded this and occupied the country. The UK exiled Reza Shah and took control of communications. The UK placed the exiled king's son, Mohammad Reza Shah Pahlavi, onto the throne.
In 1942 USA troops took control of the country's railway line.
After the end of World War II, the USA, UK and Russia withdrew as agreed with the new king. However the victorious allies failed to pay promised compensation for the use of Iran as a supply route during the War.
Free elections brought reformer Mohammed Mossadeq to power.
