quality:corruption, linguistic:translation
Military

In Baghdad there were many Abbasid military leaders who were or said they were of Arab descent. However, it is clear that most of the ranks were of Iranian origin, the vast majority being from Khorasan and Transoxiana, not from western Iran or Azerbaijan. Most of the Khorasani soldiers who brought the Abbasids to power were Arabs.

The standing army of the Muslims in Khorasan was overwhelmingly Arab. The unit organization of the Abbasids was designed with the goal of ethnic and racial equality among supporters. When Abu Muslim recruited officers along the Silk Road, he registered them based not on their tribal or ethno-national affiliations but on their current places of residence. Under the Abbasids, Iranian peoples became better represented in the army and bureaucracy as compared to before. The Abbasid army was centred on the Khorasan Abna al-dawla infantry and the Khurasaniyya heavy cavalry, led by their own semi-autonomous commanders (qa'id) who recruited and deployed their own men with Abbasid resource grants. al-Mu‘tasim began the practice of recruiting Turkic slave soldiers from the Samanids into a private army, which allowed him to take over the reins of the caliphate. He abolished the old jund system created by Umar and diverted the salaries of the original Arab military descendants to the Turkic slave soldiers. The Turkic soldiers transformed the style of warfare, as they were known as capable horse archers, trained from childhood to ride. This military was now drafted from the ethnic groups of the faraway borderlands, and were completely separate from the rest of society. Some could not speak Arabic properly. This led to the decline of the caliphate starting with the Anarchy at Samarra.

Although the Abbasids never retained a substantial regular army, the caliph could recruit a considerable number of soldiers in a short time when needed from levies. There were also cohorts of regular troops who received steady pay and a special forces unit. At any moment, 125,000 Muslim soldiers could be assembled along the Byzantine frontier, Baghdad, Medina, Damascus, Rayy, and other geostrategic locations in order to quell any unrest.

The cavalry was entirely covered in iron, with helmets. Similar to medieval knights, their only exposed spots were the end of their noses and small openings in front of their eyes. Their foot soldiers were issued spears, swords, and pikes, and (in line with Persian fashion) trained to stand so solidly that, one contemporary wrote "you would have thought them held fast by clamps of bronze".

The Abbasid army amassed an array of siege equipment, such as catapults, mangonels, battering rams, ladders, grappling irons, and hooks. All such weaponry was operated by military engineers. However, the primary siege weapon was the manjaniq, a type of siege weapon that was comparable to the trebuchet employed in Western medieval times. From the seventh century onward, it had largely replaced torsion artillery. By Harun al-Rashid's time, the Abbasid army employed fire grenades. The Abbasids also utilized field hospitals and ambulances drawn by camels.