Khorasan in its proper sense comprised principally the cities of Balkh, Herat and Ghazni (now in Afghanistan), Nishapur and Tus (now in Iran),Merv (now in Turkmenistan), and Samarqand and Bukhara (now in Uzbekistan). However, the name has been used in the past to cover a larger region that encompassed most of Transoxiana and Soghdiana[3] in the north, extended westward to the Caspian Sea, southward to include theSistan desert and eastward to the Hindu Kush mountains in Afghanistan.[4] Arab geographers even spoke of its extending to the boundaries of ancient India,[2] possibly as far as the Indus valley, in what is now Pakistan.[1] Sources from the 14th to the 16th century report that Kandahar,Ghazni and Kabulistan in Afghanistan formed the eastern part of Khorasan, overlapping with Hindustan.[5][6]
In the Islamic period, Persian Iraq and Khorasan were the two important territories. The boundary between these two was the region surrounding the cities of Gurgan and Damghan.[4] In particular, the Ghaznavids, Seljuqs and Timurids divided their empires into Iraqi and Khorasani regions. The adjective Greater is added these days to distinguish the historical region from the Khorasan province of Iran, which roughly encompasses the western half of the historical Khorasan.[7] It is also used to indicate that ancient Khorasan encompassed a loose collection of territories individually known by other popular names, such as Bactria, Khwarezmia, Sogdiana, Transoxiana, and Sistan or ABefore the region was conquered by Alexander the Great in 330 BC, it was part of the Achaemenid Empire and prior to that it was occupied by the Medes. The region that became known as Khorasan in geography of Eratosthenes was called Ariana at that time, which made up part of Greater Iran or the land where Zoroastrianism was the dominant religion. The southeastern region of Ariana fell to the Kushan Empire in the 1st century AD. The Kushan rulers introduced Buddhism in the Hindu Kush and nearby areas, in what is now Afghanistan. Numerous Buddhist temples and buried cities have been found in Afghanistan.[12][13] However, the region of Ariana (or Khorasan) remained predominantly Zoroastrian. One of the three great fire-temples of the Sassanids "Azar-burzin Mehr" is situated near sabzevar in Iran. The boundary of the region began changing until the Kushans and Sassanids merged together to form the Kushano-Sassanian civilization.
During the Sassanid era, the Persian Empire was divided into four quarters, Khvarvaran in the west, Bakhtar in the north, Nīmrūz in the south and Khorasan in the east next to Sind or Hind. Khorasan in the east saw some conflict with the Hephthalites who became the new rulers in the area but the borders remained stable. Being the eastern parts of the Sassanids and further away from Arabia, Khorasan quarter was conquered after the remaining Persia. The last Sassanid king of Persia, Yazdgerd III, moved the throne to Khorasan following the Arab invasion in the western parts of the empire. After the assassination of the king, Khorasan was conquered by Muslim troops in 647 AD. Like other provinces of Persia it became one of the provinces of Umayad dynasty.
The first movement against the Arab invasions was led by Abu Muslim Khorasani between 747 and 750. He helped the Abbasids come to power but was later killed by Al-Mansur, an Abbasid Caliph. The first independent kingdom from Arab rule was established in Khorasan by Tahir Phoshanji in 821, but it seems that it was more a matter of political and territorial gain. In fact Tahir had helped the Caliph subdue other nationalistic movements in other parts of Persia such as Maziar's movement in Tabaristan.
Other major independent dynasties in Khorasan were the Saffarids (861-1003,) Samanids (875-999), Ghaznavids (963-1167), Seljuqs (1037–1194),Khwarezmids (1077–1231), Ghurids (1149–1212), and Timurids (1370–1506). It should be mentioned that some of these dynasties were not Persian by ethnicity, nonetheless they were the advocates of Persian language and were praised by the poets as the kings of Iran.
Among them, the periods of the Ghaznavids of Ghazni and Timurids of Herat are considered as the most brilliant eras of Khorasan's history. During these periods, there was a great cultural awakening. Many famous Persian poets, scientists and scholars lived in this period. Numerous valuable works in Persian literature were written. Nishapur, Herat, Ghazni and Merv were the centers of all these cultural developments.
From the 16th century to the early 18th century, Khorasan was ruled by the Shia Safavid dynasty while the region to the east by the Sunni Khanate of Bukhara and the southeast by the Sunni Mughul Empire.[14] It was conquered in 1717, along with the rest of Persia, by the Ghilzai Afghans from Kandahar and became part of the Hotaki dynasty.[15][16] Following the assassination of Nader Shah Afshar in 1747, Khorasan was annexed with the Durrani Empire or modern-day Afghanistan.[17] In the early 19th century, much of Khorasan's western territory fell to the Qajar dynasty of Persia and remained as Iranian territory until modern day. Some of its northern areas were left under the Tsardom of Russia or later the Soviet Union.rachosia.[citation needed]
