In the Western world, Persia (or its cognates) was historically the common name for Iran. In 1935, Reza Shah asked foreign delegates to use the term Iran, the historical name of the country, used by its native people, in formal correspondence. Since then, in the Western World, the use of the word “Iran” has become more common. This also changed the usage of the names for the Iranian nationality, and the common adjective for citizens of Iran changed from Persian to Iranian.
The history of Iran, commonly also known as Persia in the Western world, is intertwined with the history of a larger region, also to an extent known as Greater Iran, comprising the area from Anatolia, the Bosphorus, and Egypt in the west to the borders of Ancient India and Syr Darya in the east, and from the Caucasus and the Eurasian Steppe in the north to the Persian Gulf and the Gulf of Oman in the south.