Iran has been inhabited by humans since pre-historic times and recent discoveries have begun to shed light upon what ancient culture was like in Iran, centuries before the earliest civilizations arose in nearby Mesopotamia.

The written history of Persia (Iran) begins in about 3200 BCE with the Proto-Elamite civilization, followed by the Elamites. The arrival of the Aryans (Indo-Iranians), and the establishing of the Median dynasty culminated in the first Persian Empire, the Achaemenid Empire (648–330 BCE), founded by Cyrus the Great.

Cyrus the Great created the Cyrus Cylinder, considered to be the first declaration of human rights. He was the first king whose name was suffixed with the word "Great" and the first Shah of Iran to be properly called. Cyrus" seminal ideas greatly influenced later human civilizations; as shown in this documentary movieclip, Cyrus" principles of ruling - advocating "love" rather than "fear" - has influenced the current U.S. constitution.(movieclip 11:23 "In Search of Cyrus the Great")

After Cyrus" death, his son Cambyses ruled for eight years (530-522 BC) and continued his father"s work of conquest, making significant gains in Egypt. A power struggle followed Cambyses" death and, despite his tenuous connection to the royal line, Darius was declared king (ruled 522-486 BC). He was to be arguably the greatest of the ancient Persian rulers.

Darius" first capital was at Susa, and he started the building programme at Persepolis. He built a canal between the Nile and the Red Sea, a forerunner of the modern Suez Canal. He improved the extensive road system, and it is during his reign that mention is first made of the Royal Road (shown on map), a great highway stretching all the way from Susa to Sardis with posting stations at regular intervals.

Major reforms took place under Darius. Coinage was introduced to the World - the daric (gold coin) and the shekel (silver coin) - and he greatly increased the efficiency of the administration. The Old Persian language appears in royal inscriptions, written in a specially adapted version of cuneiform.(Movieclip, "Persepolis Recreated" 41:14) .

Under Cyrus the Great and Darius the Great, the Persian Empire eventually became the largest and most powerful empire in human history up until that point, ruling and administrating over most of the then known world.

Alexander the Great, also known in the Zoroastrian Middle Persian Arda Wiraz Nāmag as "the accursed Alexander" (due to his conquest of the Persian Empire and the destruction of its cities, including the capital Persepolis), conquered Persia in 333 BCE only to be followed shortly by two more vast and unified Persian empires that shaped the pre-Islamic identity of Iran and Central Asia: the Parthian (250 BCE – 226 CE) and Sassanian (226 – 650 CE) dynasties. The latter dynasties also defeated the Roman empire at the height of its power on several occasions.

The Silk Road, connecting Persia with China was significant not only for the development and flowering of the great civilizations of China, ancient Egypt, Mesopotamia, Persia, India and Rome but also helped to lay the foundations of our modern world.