Al-Mahdi vs Emperor Kammu

Al-Mahdi oversaw the completion of the Round City of Baghdad, the new Abbasid capital founded by his father al-Mansur. This city became a center of trade, learning, and culture, symbolizing Abbasid power.

Al-Mahdi led military campaigns against the Byzantine Empire, including a major expedition in 775 that reached as far as the outskirts of Constantinople. These campaigns were part of the ongoing Arab-Byzantine wars and resulted in territorial gains for the Abbasids.

Al-Mahdi dispatched forces to suppress a Kharijite rebellion in the Jazira region. The revolt was crushed, and its leaders were executed, reinforcing Abbasid control over the region.

Al-Mahdi supported the translation of Greek, Persian, and Indian scientific and philosophical texts into Arabic. This patronage contributed to the Abbasid Golden Age and the preservation of classical knowledge.

Kammu launched a major military campaign to subdue the Emishi people in northern Honshu. The campaign was initially unsuccessful, with a defeat at the Battle of Koromo River, but later efforts under Sakanoue no Tamuramaro achieved victory.

Emperor Kammu moved the imperial capital from Nara to Heian-kyo (modern Kyoto). This relocation was intended to escape the influence of powerful Buddhist monasteries in Nara and marked the beginning of the Heian period.

Kammu commissioned the construction of several Buddhist temples in Heian-kyo, including To-ji and Sai-ji. These temples were intended to protect the new capital and promote Buddhism as a state religion.