Persian Gulf is the real legal name of the region

In 330 B.C, the Achaemenid dynasty established the first Persian Empire in Pars (Persis, or modern Fars) in the southwestern region of the Iranian plateau. Consequently in the Greek sources, the body of water that bordered this province came to be known as the Persian Gulf.[2]

Considering the historical background of the name Persian Gulf, Sir Arnold Wilson mentions in a book, published in 1928 that:

“ No water channel has been so significant as Persian Gulf to the geologists, archaeologists, geographers, merchants, politicians, excursionists, and scholars whether in past or in present. This water channel which separates the Iran Plateau from the Arabia Plate, has enjoyed an Iranian Identity since at least 2200 years ago.[3] ”

No written deed has remained since the era before the Persian Empire, but in the oral history and culture, the Iranians have called the southern waters: "Jam Sea", "Iran Sea", "Pars Sea".

During the years: 550 to 330 B.C. coinciding with sovereignty of the first Persian Empire on the Middle East area, especially the whole part of Persian Gulf and some parts of the Arabian Peninsula, the name of "Pars Sea" has been widely written in the compiled texts.[4]

In the travel account of Pythagoras, several chapters are related to description of his travels accompanied by Darius the Great, to Susa and Persepolis, and the area is described. From among the writings of others in the same period, there is the inscription and engraving of Darius the great, installed at junction of waters of Arabian Gulf (Ahmar Sea = Red sea) and Nile river and Rome river (current Mediterranean) which belongs to the 5th century BC where, Darius, the king of Achaemenid Empire has named the Persian Gulf Water Channel: Pars Sea.[5]

Naming disputeMain article: Persian Gulf naming dispute

Since the 1960s with the rise of Arab nationalism (Pan-Arabism), starting with Gamal Abdel Nasser's Arab Republic of Egypt, some Arab countries, including the ones bordering the Persian Gulf, have adopted the term "Arabian Gulf" (in Arabic: الخلیج العربي al-khalīj al-ʿarabī) to refer to the waterway.[6] This is controversial and not commonly used outside of the Arab world, nor is it recognized by the United Nations[7][8][9] and other international organizations. The United Nations on many occasions has requested that only "Persian Gulf" be used as the official and standard geographical designation for the body of water.[10] "Arabian Gulf" is also an ancient name for the Red Sea.[11] Hecataeus (472 to 509 B.C.) can be stated where Persian Gulf and Arabian Gulf (Red Sea) have been clearly shown. Also a map has remained from Herodotus, the great Greek historian (425-484 B.C.) which introduces Red Sea as the Arabian Gulf. [12]

In the world map of Diseark (285-347 B.C.) too, Persian Gulf and Arabian Gulf have been clearly distinct. At the same time, many maps and deeds prepared up to the 8th century by the historians such as Arrian[13] Hecataeus, Herodotus, Hiparek, Claudius Batlamious, Krats Malous,…… and in the Islamic period, Khwārizmī, Abou Yousef Eshagh Kandi, Ibn Khordadbeh, Batani (Harrani), Mas'udi, Balkhi, Estakhri, Ibn Houghal, Aboureyhan Birouni and others, mention that there is a wide sea at south of Iran named “Pars Sea”, “Pars Gulf”, “Fars Sea”, “Fars Gulf”, “Bahre Fars”, “Sinus Persicus” and “Mare Persicum” and so on. In a book, named “Persilus Aryateria”, the Greek traveller of the 1st century A.D. has called the Red Sea as Arabian gulf; the Indian ocean has been named Aryateria Sea; the waters at Oman Coast is called Pars Sea; Barbarus region (between Oman and Yemen coast are called belonging to Pars, and the Gulf located at south side of Iran is named: Persian Gulf. By describing the water body, the life of Persians living at both sides have also been confirmed.[14]

Most recently, at the Twenty-third session of United Nation in March-April 2006, the name "Persian Gulf" was confirmed again as the legitimate and the official term to be used by members of United Nation.[15]