Considered one of the oldest literature in the entire world, Persian literature stretches across two and half millennia although much of the initial works are now lost. The lost works belonged to the pre-Islamic era. Persian literature stretches many lands and its greatest sources include the entire of present day Iran, Iraq, Turkey, Caucasus, portions of Central and South Asia too. Even the language was an official or native tongue for many in this vast region.
Take for instance their most loved poet – Rumi. He was born in what is now modern day Afghanistan. He wrote in Persian but spent most of his time living in Konya, the capital at the time of Seljuks, which was in Anatolia. Then there were the Ghaznavids who took over large territories throughout South and Central Asia. In the process they adopted Persian as their chosen court language. Quite naturally, Persian literature emanated from Azerbaijan, Mesopotamia, Iran, parts of Tajikistan, Pakistan, India and some portions of Turkey as well as Central Asia. However, not everything in Persian literature comes in the Persian script. It also includes the work of ethnic Persians in other languages like Arabic and Greek. Then again, those who used Persian language for their literature do not automatically fall under the Persian literature!
Some call Persian the greatest literatures ever of humanity since it has so many sections and the fact that is survived as long as it did. Its root lies in the works surviving from the Old and middle Persian eras. However, you can find a lot of work that goes back to 5th century BC – Achaemenid’s inscriptions are from this time including the Behistun inscription. Rest of the surviving Persian literature though comes after the Islamic conquests around 650 CE. When Abbasids came to power a century later, the Iranians became scribes and bureaucrats thus the literature grew bountiful with writers and poets getting commissions. During this time, Iranians wrote not just in Persian but also Arabic. Some Persian poets are equally revered in the West such as Nezami, Attar, Hafiz, Ferdowsi and Omar Khayyam.