However (as expected) AP can't get the facts straight: Persia, the ancient name for non-Arab Iran
Persia was the name the Greek, Romans and later other foreigners called the Country/Empire, referring to the people of the Fars province.
Iran (previously Aryanam), meaning "Land of the Aryans" has been the natives' name for their country since ancient times, long before Islam appeared.
1935 Reza Shah Pahlevi officialy made Iran the name to be used by natives and foreigners alike.