By historic Iran, we mean the time about a century and a half ago that the Old Persian was decoded. The discovery of cuneiform and its alphabet has made major revolution in reading the inscriptions and scriptures. This decoding helped archeologists understand that the official Iranian history dates back to 2500 years ago which is around the beginning of the Achaemenid era. Before this era, the history is only limited to the civilization of Elam (Elamite) and Medes which were mostly focusing on their role in the formation of the first great empire of the world i.e. Achaemenid Empire.
The history and culture of the Iranian have been always important in the course of world history, mainly because of the country’s geographical location. Each dynasty in Iran had a great impact on the religion, writing, architecture, culture and civilization of the world.
The important issue in Iranian history is the relation of nomadic tribes and residents and their effects on the designation and dethronement of rulers. In general, it can be said that the changes in Iranian regime were caused either by conflicts between indigenous people or by the invasion of foreign nations that led to the establishment of new dynasties. The entry of these tribes into Iran was always accompanied by conflict, war and bloodshed with the locals, however, these tribes brought their own culture, art and industry to Iran and got accustomed to the culture and art of the locals as well. The result of this combination was the emergence of a more powerful and advanced government. It should be mentioned that the study of culture and politics in Iran is not possible unless we get to know the ethnic groups and the formation process of ruling dynasties.
Therefore, in order to understand the historic Iran, we have to start with Elamites, the indigenous people of the Iran plateau. Contemporary Elamites were large powers such as Babylon, Sumer and Assyria. The Assyrian inscriptions show the power of Elam well enough and present Iran as a country which has had civilization and culture since 3500 B.C. Elamites chose Susa as their capital and ruled over the regions of Khuzestan, Lorestan and Bakhtiari mountains. They were overthrown by the Assyrian king, Ashurbanipal in 645 B. C.
The folk of Aryan was divided into several tribes once they immigrated to Iran Plateau and each of them scattered in different parts of the Plateau. The most important of them were the three tribes of the Medes, Persis and Parthia.
At the beginning of the 7th century B.C., Diocese initiated the Medes Dynasty with Ecbatana as the capital and a land, they were also inhabiting in Azerbaijan and Kurdistan and several years later, they managed to eliminate the great Mesopotamian power i.e. Assyrians, but they were eventually dethroned by the tribe of Persis.
The Persis people established the great Achaemenid Empire ruled by Cyrus the Great in 550 B.C. During this period, Iran reached its peak of political power and its greatest geographical extent. The ruling government managed to eliminate Babylon and had many wars with the Greeks. At the time of Darius and Xerxes, the empire was stabilized and reached its peak. However, like any other dynasties, they suffered from internal disputes and decay of power. Eventually, they were dethroned by the Greek army ruled by the Great Alexander in 330 B.C.
After the death of Alexander, his territory was divided among his commanders, and Iran fell into the hands of Seleucus and his successors for 73 years. Some historians prefer to call this period the Interval Era because of the introduction of the philhellenic culture (Greek culture) to Iran and its impacts on Iranian art and civilization.
Gradually the Parthian managed to remove some areas from the domination of the Seleucids, and eventually, in 247 B. C., Arsaces I founded Parthian dynasty that held power until 224 A. D. i.e. for 471 years. The Parthian government was the only Iranian power which had Feudal system of governing. The most salient features of this era were freedom of speech and religious tolerance. The Parthians are also known for their numerous attrition battels against Romans, the wars that were mostly fruitless and did nothing but to weaken the country. The Parthian governance which is known as the longest dynasty in Iran was finally destroyed by Ardashir Babakan– the founder of Sassanid Empire- after about five centuries of ruling.
Sassanid, as the last pre-Islamic dynasty, came to the throne from the city of Persis whose inhabitants called it Iranshahr and considered themselves the descendants of the Achaemenid. The Sassanid dynasty began its governance around 224 A.D. by Ardashir Babakan, unlike Parthians, it was ruled through a central government. The official religion in this period was Zoroastrianism and they did not separate ruling from religion, hence the power of the Magus and the Zoroastrian priests in this period was undeniable.
The Sasanians managed to reign over Iran for 427 years. The Kings had a tendency to be luxurious and aristocratic and as a result, the social gap between commoners and courtiers increased. Besides, dissatisfaction was observed among people due to religious rigors of Zoroastrian priests. Finally, Sassanid government started its period of decline and was heavily defeated by the Arabs. With the destruction of Sassanid rule, the Islamic time began.