The history of Isfahan can be traced back to the Palaeolithic period. In recent discoveries, archaeologists have foundartifacts dating back to the Palaeolithic, Mesolithic, Neolithic, Bronze and Iron ages.
During the Median dynasty, this commercial entrepôt began to show signs of a more sedentary urbanism, steadily growing into a noteworthy regional centre that benefited from the exceptionally fertile soil on the banks of the Zayandehrud River in a region called Aspandana or Ispandana. Once Cyrus the Great (reg. 559–529 BCE) unified Persian and Median lands into the Achaemenid Empire (648–330 BCE), the religiously and ethnically diverse city of Isfahan became an early example of the king's fabled religious tolerance. It is said that after Cyrus the great freed the Jews from Babylon some Jews returned to Jerusalem whereas some others decided to live in Persia and settle in what is now known as Isfahan. But, actually this happened later in the Sasanid period when a Jewish colony was made in the vicinity of the Sasanid Gay.
The Parthians (250 BCE – 226 CE) continued the tradition of tolerance after the fall of the Achaemenids, fostering the Hellenistic dimension within Iranian culture and political organization introduced by Alexander the Great's invading armies. Under the Parthians, Arsacid governors administered a large province from Isfahan, and the city's urban development accelerated to accommodate the needs of a capital city.
The next empire to rule Persia, the Sassanids (226 – 652 CE), presided over massive changes in their realm, instituting sweeping agricultural reform and reviving Iranian culture and the Zoroastrian religion. The city was then called by the name Gay and the region by the name Aspahan or Spahan. The city was governed by "Espoohrans" or the members of seven noble Iranian families who had important royal positions, and served as the residence of these noble families as well. Extant foundations of some Sassanid-era bridges in Isfahan suggest that the kings were also fond of ambitious urban planning projects. While Isfahan's political importance declined during the period, many Sasanian princes would study statecraft in the city, and its military role developed rapidly. Its strategic location at the intersection of the ancient roads to Susa and Persepolis made it an ideal candidate to house a standing army, ready to march against Constantinople at any moment. The words 'Aspahan' and 'Spahan' are derived from the Pahlavi or Middle Persian meaning 'the place of the army'.Although many theories have been mentioned about the origin of Isfahan, in fact little is known of Isfahan before the rule of the Sasanian dynasty (c. 224–c. 651 CE). The historical facts suggest that in the late 4th and early 5th centuries Queen Shushandukht, the Jewish consort of Yazdegerd I (reigned 399–420) settled a colony of Jews in Yahudiyyeh (also spelled Yahudiya), a settlement 3 kilometres northwest of the Zoroastrian city of Gay (the Achaemid and Parthian 'Gabae' or 'Gabai', the Sasanid 'Gay' and the Arabicized form 'Jay') that was located just on the northern bank of the Zayanderud River. The gradual population decrease of Gay or Jay and the simultaneous population increase of Yahudiyyeh and its suburbs after the Islamic conquest of Iran resulted in the formation of the nucleus of what was to become the city of Isfahan. It
When the Arabs captured Isfahan in 642, they made it the capital of Al-Jibal (“the Mountains”) province, an area that covered much of ancient Media. Isfahan grew prosperous under the Persian Buyid (Buwayhid) dynasty, which rose to power and ruled much of Iran when the temporal authority of the Abbasid caliphs waned in the 10th century. The Turkish conqueror and founder of the Seljuq dynasty, Toghril Beg, made Isfahan the capital of his domains in the mid-11th century; but it was under his grandson Malik-Shah I(reigned 1073–92)that the city grew in size and splendour.
The city's golden age began in 1598 when the Safavid ruler Shah Abbas I (reigned 1588–1629) made it his capital and rebuilt it into one of the largest and most beautiful cities of the 17th century. In 1598 Shah Abbas the Great moved his capital from Qazvin to the more central and Persian Isfahan, called Ispahān in earlyNew Persian.
Isfahan declined once more, and the capital was subsequently moved to Mashhad and Shiraz during the Afsharid and Zand periods respectively until it was finally settled in Tehran in 1775 .
Today Isfahan, the third largest city in Iran, produces fine carpets, textiles, steel, and handicrafts. Isfahan also has nuclearexperimental reactors as well as facilities for producing nuclear fuel (UCF). Isfahan has one of the largest steel-producing facilities in the entire region, as well as facilities for producing special alloys.
The city has an international airport and is in the final stages of constructing its first Metro line.
Over 2000 companies work in the area using Isfahan's economic, cultural, and social potentials. Isfahan contains a major oil refinery and a large airforce base. HESA, Iran's most advanced aircraft manufacturing plant (where the IR.AN-140 aircraft is made), is located nearby. Isfahan is also becoming an attraction for international investments, like investments in Isfahan City Center, which is the largest shopping mall in Iran and the largest shopping mall with a museum in the world and has the largest indoor amusement park in the middle-east.
Isfahan hosted the International Physics Olympiad in 2007.