The Persian Empire was a series of dynasties that lasted from the 6th century BC to the 20th century AD. At its height, the empire stretched from the Indus Valley in India to the Balkan Peninsula in Europe and southwards to Egypt. Five dynasties ruled the Persian Empire before it collapsed in 1925. Throughout the centuries, the territorial boundaries of the empire changed severally, but the political and economic center remained in present-day Iran.
The names Persia and Iran are often used interchangeably to refer to the same country. The center of the ancient kingdom of Persia was located in present-day Iran. The use of the term Persia to refer to modern-day Iran was popularized by the west due to the ancient Greek authors. The word “Persia” was derived from “Pers” which is a western version of "Pars". Pars is one of the provinces of Iran and the seat of the ancient Persian Empire.
The Persian Empire began around the year 550 BCE when King Cyrus the Great of Achaemenid established dominance over the Aryan Kingdom in the 6th century. The king brought together the Aryan empires and established the Achaemenid Persian Empire. The king sought to expand his kingdom by conquering the non-Aryan territories especially west of Persia. The empire extended from the Indus valley in the east to Greece in the west and southwards into Egypt and Ethiopia. The empire quickly expanded and became the largest in the world at the time. In 330 BCE, Alexander of Macedonia took over the territory and established the Seleucid Empire. In 248 BCE the Aryan Parthians overthrew the Seleucids and established the Parthian Empire. The Parthians ruled until 226 CE when the Persians took over for the second time and created the Sasanian Empire. At the beginning of the 16th century, the Arabs took over the control of the empire by establishing the Safavid dynasty, and Afsharid dynasties.
The name “Iran” was derived from "Aryan” which was the earliest empire before the Persian empire was conceived. During the rule of the Persians, the Aryan language, religions, and culture spread across the empire and became a unifying factor. The Iranians have never referred to themselves as Persians or to their country as Persia. The use of the word was popularized by the west. In the 1930s, Reza Shah Pahlavi, the then ruler of Iran sought to formalize the use of the name Iran in the West and therefore issued an international circular requesting foreign diplomatic missions in the country to address the state as Iran and not Persia. On March 21, 1935, the country became internationally recognized as Iran.
Victor Kiprop August 20 2019 in World Facts