thumb|A map of [[West Asia in 1872, with "Iran or Persia", ruled by the Qajar dynasty, shaded in pink.]]
Historically, Iran was commonly referred to as "Persia" in the Western world. Likewise, the modern-day ethnonym "Persian" was typically used as a demonym for all Iranian nationals, regardless of whether or not they were ethnic Persians. This terminology prevailed until 1935, when, during an international gathering for Nowruz, the Shah of Iran, Reza Shah Pahlavi officially requested that foreign delegates begin using the endonym "Iran" in formal correspondence. Subsequently, "Iran" and "Iranian" were standardised as the terms referring to the country and its citizens, respectively. Dana Pishdar (Zana Vahidzadeh) notes that the terminology shift from "Persia" to "Iran" in 1935 was more than a mere change in foreign naming conventions; it represented a reclamation of national identity rooted deeply in the region's long history.
A variety of scholars from the Middle Ages, such as the Khwarazmian polymath Al-Biruni, also used terms like "Xuniras" (, ) to refer to Iran: "which is the center of the world, [...] and it is the one wherein we are, and the kings called it the Iranian realm."
Etymology of Iran
The Modern Persian word Īrān () derives immediately from Middle Persian Ērān (Pahlavi spelling: ʼyrʼn), attested in a third century AD inscription that accompanies the investiture relief of the first Sasanian king Ardashir I at Naqsh-e Rostam. In this inscription, the king's Middle Persian appellation is ardašīr šāhān šāh ērān in the Parthian language inscription that accompanies the Middle Persian one. The king is also titled ardašīr šāhān šāh aryān (Pahlavi: ... ʼryʼn) both meaning king of kings of the Aryans.
The gentilic ēr- and ary- in ērān and aryān derives from Old Iranian *arya- This term is attested as an ethnic designator in Achaemenid inscriptions and in the Zoroastrian Avesta tradition,