The Abbasid Caliphate, also known as the Arabian Empire, was the third caliphate, an Islamic state regarded as succeeding the prophet Muhammad. It was established in 750 in the wake of a revolution against the Umayyad Caliphate. Because their banners were black, they were known to the Tang as the "Black Arabs" (黑衣大食).
The long period of Abbasid rule is often remembered as the Islamic Golden Age for being a zenith of scientific and artistic flowering across the Islamic world. Eventually, Abbasid power declined, and their control was reduced to only the territory around their capital of Baghdad by the time of the Crusades although their caliphs continued to wield spiritual prestige. In 1258, the Sack of Baghdad by Hülegü Khan of the Mongol Empire spelled an apocalyptic end to not just Abbasid cultural power but to the intellectual advances of Islamic society, as the city's philosophers and scientists were exterminated and its libraries and academies razed to the ground. The surviving Abbasids lingered on for a time in Egypt behind the Mamluk Sultanate until finally being extinguished by the Ottoman Empire in 1517. 
- Assassin's Creed: Dynasty (first appearance)
- Assassin's Creed: Valhalla (mentioned only)
- Wrath of the Druids (mentioned only)
- Assassin's Creed Valhalla: Geirmund's Saga (as "Serkland")