The five centuries of the Abbasid caliphate, from the foundation of Baghdad in 762 to the Mongol sack of the city in 1258, are the great classical period of Arabic literature. The court of Harun al-Rashid and his successors patronised an unprecedented body of poetry, prose, philosophy, and translation; Greek philosophy, Persian literature, and Indian science all entered the Arab world through the Abbasid translation movement.
The major poets of the period — Abu Nuwas, al-Mutanabbi, al-Ma'arri — set the standards by which subsequent Arabic poetry would be judged for the next millennium. Al-Jahiz founded Arabic literary prose; al-Tabari produced the great history; the philological school of Basra and Kufa codified the grammar of the language.
It is also the period of the maqama (the rhymed prose narrative pioneered by al-Hamadhani and perfected by al-Hariri), the assembly of The Thousand and One Nights in something like its current form, and the great intellectual flourishing in Andalusia in parallel: Ibn Hazm, Ibn Tufayl, Ibn Rushd (Averroes).