Iran has undoubtedly played a most significant role in the evolution of human civilization. What we call Iran today is the remainder of an ancient civilization. Archeological findings indicate that human beings lived in the various parts of Iran as long as 15,000 years ago. In the caves known as Tamtameh, Bisotoun and Houtu and at many other sites, indicate that there were human settlements in Iran from the Food Gathering Age, down to the Stone Age when the human race learnt to make simple stone tools and beyond. But, the history of human life in Iran, prior to 5,000 years ago is still somewhat unclear, and requires a great deal more of explorations, excavations and study which are presently underway.
Since 5,000 years ago, however, history is much clearer. Between 4,000 and 5,000 years ago a large group of Indo-Europeans moved down to the Iranian Plateau, from a region extending from the Caspian to the Black Sea. Among them, were the Medes, a tribe of the Aryan race, who managed to peacefully come to terms with the indigenous people and dominated a vast area of the Iranian plateau.
Another large group was the Persians, comprising of many tribes. The Medes and the Persians were rivals, constantly at war with each other till about the middle of the 1st millenium BC. This rivalry came to an end in 550 BC when the king of the Persians, Kourosh or Cyrus overcame the Medes and established the kingdom of the Persians and the Medes, ruled by the Achaemenid dynasty, the first modern and all-embracing government.
The Achaemenids ruled over a large territory, mostly conquered by Cyrus which extended, in 330 BC, from the Caucasus region - which it included - in the north, down to the Sea of Oman in the south, and from India in the east to the Adriatic Sea in the west. The seat of this vast empire was Takhte Jamshid (Persepolis) in today's Fars Province whose ruins are still evidence of a splendid empire and a great civilization. During their era agriculture made enormous progress. Also, ironworks, stone carving, use of stone in building, architecture, construction, use of gold and copper... developed remarkably.
The Achaemenids had a very effective and intricate fiscal and accounting system and usually used coins in their transactions.
In 330 BC, Alexander the Macedonian, defeated the Achaemenid King Darius III conquered Persia (Iran) and thus ended the Achaemenid dynasty. After the death of Alexander, one of his great generals took over the Iranian territories and founded the Selucid dynasty. The Selucids ruled over Iran or Persia, down to 247 BC, when Ashkanian, also known as Parthians, overthrew the Selucids and took over the kingdom. During the ear of the Parthians roads were improved and the water transfer systems or qanats were refined considerably. Parthians ruled the territory down to 224 AD when Ardeshir of Babakan put an end to this dynasty and founded the dynasty of the Sassanids.
The Sassanid empire had a powerful central government. During the era of this dynasty the society was divided into strict strata, the cast system, with the Zoroastrian priests at the top and farmers at the bottom level of society. The Sassanids were insistent that roads, bridges, qanats and palaces should be improved and many new ones built. Many of these remain today as archeological sights. Because of the cast system, heavy taxes on the lower strata, and corruption, the Sassanids gradually declined and could not withstand the Moslem invasion which began in 645. The Persian army of Yazdgerd III was defeated by the Moslem forces.
The Umayyads were the first Arab dynasty to rule over Iran. Contrary to Islamic teachings they treated the Iranians as inferior to Arabs and were often cruel to them. Their harsh treatment of Iranian gave rise to unrest and repeated uprisings which finally toppled the Umayyads who were replaced by the Abbasid dynasty.
Acceptance of Islam resulted in many changes in Iranian culture and traditions. Zorastrianism lost much of its strength and popularity. Arabic became the official language of the country for many years and the Arabic alphabet was adopted by Iranians for good. It took about two centuries for Iranian governments to emerge as generals governing various provinces declared independence.
The Taherids were the first independent Iranian rulers founded by an Iranian general called Tahir who declared independence in Khorassan in 816. In 872, however, another Iranian, Yaqub Leith Saffari, overthrew the Taherids and founded the Saffari dynasty, which was in turn toppled by the Samanids in 903.
Then the Samanids became independent rulers in Khorassan from 903 to 999 AD, and also captured the northern parts of the country which the Alavids had ruled simultaneously.
Thus, after 200 years or so the Iranians, who had accepted Islam put an end to Arab rule. From the era of the Samanids Iranian culture and literature were revived. The Samanids were ultimately overthrown by the Ghaznavid Turks.
Meanwhile the pro-Alavi Ale Bouyeh continued to rule in some parts of Iran. Ghaznavids' vast empire succumbed to the next wave of the Turks moving towards Iran, the Seljuqs, who took over the power in 1037.
The Seljuqs enlarged the Iranian territory to almost the extent it had occupied in the era of the Sassanids. But soon there were conflicts among the various Seljuqs, branches or tribes emerged and divided the kingdom: Kharazmshahians, Atabakans,... ...
In the 11th century AD, Hassan Sabbah created and led the Hashshashin (whence the word assassin) movement from his base in a stronghold built on the top of Alamoot mountain.
Then came disaster. The Mongols attacked Iran in 1220, and not only dethroned the local dynasties, but seriously damaged Iranian culture and civilization. Man historic monuments and libraries were ruined or burnt down, and the inhabitants of many towns were massacred, amidst them many poets, scholars and scientists. Those who remained alive fled the country. The rule of the Abbasi caliphs also came to an end. The Mongols tried hard to change the culture and ways of Iranians but eventually, the reverse happened: They themselves became Moslems and were absorbed into the Iranian culture.
The wound caused by the early Mongols had not yet healed before Teymour (Tamerlane) r invaded Iran in 14th century, ruining many towns and massacring far too many people. Teymour's empire rapidly declined after he died, however, and was dissolved in the year 1500, at the hand of Shah Esmail the Safavid.
Shah Esmail was a Shia (friend of Imam Ali (AS) and his descendants). He established a dynasty based on the Shia thoughts as the official religion of Iranians. The Safavid developed a powerful central government, built many impressive monuments and helped arts and artists greatly.
Shah Abbas I moved the Safavid capital from Qazvin to Isfahan where he and his successors built a good number of magnificent monuments. There were numerous wars between Safavid Iran and the Ottoman empire, which were rivals.
Early 18th century large group of Afghans invaded Iran and toppled the weakened Safavid dynasty.
An Iranian general by the name of Nader Gholi Afshar gathered an army, defeated the Afghans and ultimately founded the Afshar dynasty in 1736 AD. He recaptured those parts of Iran which the Ottomans had grabbed from Iran in the then recent times. Then he invaded India and captured parts of this country. Being harsh on his entourage, Nader was killed by a few of his generals in 1747 and his dynasty began to decline from the day of his death.
In 1750 Karim Khan Zand founded the Zand dynasty and chose the city of Shiraz to be his capital. He preferred peace and prosperity for his people. But when he died, there were many serious conflicts among his descendants.
In 1796 Agha Mohammad Khan, the chief of the Qajar tribe founded the Qajar dynasty, and was crowned in Tehran. It was during the Qajar era when Iranians became closely aquatinted with Western culture. Gradually the powers of the day, Russia, Britain and France became increasingly interested in Iran. During this era two heavy wars took place between Iran and Russia, in which Iran lost large parts of its territories. Mirza Taghi Khan Amir Kabir, the vizier (Prime Minister) of Nassereddin Shah attempted to modernize Iran and place it in line with the latest developments and the progress being made in the West. But the Qajar princes intrigued against him and had him executed.
From 1896 till 1906 Iranians put up a political movement that is generally known as the Constitutional Uprising. A parliament was finally created, which ratified a Constitution for the country's political and administrative system.
During World War I, Iran was, despite its neutrality, divided into two zones of influence: The northern parts were to be under the influence of Russian, and the British were to dominate the southern parts. The central parts were supposed to be neutral. But in 1917 the Bolshevik Revolution overthrew the Tezar and Russian forces left Iran leaving the country entirely under the influence of Britain.
At this time there were uprisings against the British in Gilan and Azerbaijan. Reza Khan, the commander of a Ghazzagh unit, put up a coup d'etat in 1920 and effectively took over the power. Finally, in 1926 Reza Khan dethroned Ahmad Shah, the last Qajar king, and proclaimed himself the first king of the Phalavi dynasty and was crowned. But during World War II, the allies, who had occupied Iran, made him abdicate in favor of his son Mohammad Reza.
The Iranian parliament declared Iran's oil industry as nationalized and thus the Oil Nationalization. Movement began. In 1951, Dr Mosaddegh became prime minister and took on the leadership of the Movement. With the help of Ayatollah Kashani, he made great progress and was about to finalize the matter.
The Shah left the country, but his generals, helped by US security forces (CIA), arranged a coup d'etat and brought back the Shah. From then till the Islamic Revolution of 1979 he ruled as a dictator subduing any resistance, or disagreement with him. For example, in 1963 the citizens of Qom led by Imam Khomeini put up an uprising against the Shah which was crushed by the Shah's forces. Imam Khomeini was sent to exile.
In 1979 the people's protests reached a climax. The Shah left the country again and Imam Khomeini returned home and took on the leadership of the Revolution. On 11th of February the Islamic Revolution reached a victory and the Pahlavi dynasty was terminated.
With the downfall of the Shah's regime, Iran's first ever republic was established and was confirmed by a 98.8% vote in a special referendum.
In 1980 Iraq attacked Iran and occupied parts of western and southern Iran. Iranians fought bravely and finally the war came to a cease-fire according to the resolution 598 of UN.
Imam Khomeini passed away in 1989 and was succeeded as the leader by the then President, Ayatollah Khameneie.
After the imposed war (with Iraq) was over, Iran managed to restore and rebuild the war damages it had sustained. Hojjatoleslam Rafsanjani was twice appointed as the President, in 1989 and 1993. Currently Hojjatoleslam Mohammad Khatami is the President. This is the second term of his presidency having been twice elected, in 1997 and 2001.