Military of the Sasanian Empire

The birth of the Sasanian army ( Artesh-e Sāsānīyān, Pahlavi Spâh سپاه, "army") dates back to the rise of Ardashir I (r. 224–241), the founder of the Sassanid Empire, to the throne. Ardashir aimed at the revival of the Persian Empire, and to further this aim, he reformed the military by forming a standing army which was under his personal command and whose officers were separate from satraps, local princes and nobility. He restored the Achaemenid military organizations, retained the Parthian cavalry model, and employed new types of armour and siege warfare techniques. This was the beginning for a military system which served him and his successors for over 400 years, during which the Sassanid Empire was, along with the Roman Empire and later the East Roman Empire, one of the two superpowers of Late Antiquity in Western Eurasia. The Sassanid army protected Eranshahr ("the realm of Iran") from the East against the incursions of central Asiatic nomads like the Hephthalites, Turks, while in the west it was engaged in a recurrent struggle against the Roman Empire.

Army
In the character of their warfare, the Persians of the Sassanid period differed greatly from their forebears under the Achaemenid kings. The principal changes which time had brought about were an almost entire disuse of the war chariot, the advance of the elephant corps into a very prominent and important position, and the increased use and pre-eminence of cavalry on the Parthian model, including both heavy cataphracts and horse-archers. Four main arms of the service were recognized, each standing on a different level: the elephants, the horse, the archers, and the ordinary footmen.

Divisions
In Pahlavi language, smaller divisions of the spāh were referred to as vasht and larger divisions were designated as gond. Interestingly, the Arabic word jond (جند), meaning "army", is derived from the latter.

Ranks

 * Erān Spahbod: Commander-in chief.
 * Spahbod: Field general.
 * Pādgospān or Padouspān (Modern Persian: پادوسبان): Commander of each of the four provincial divisions devised during the reign of Khosrau I.
 * Marzbān or Kanārang: Equivalent to Margrave or commander of the border guards; according to Procopius, it had been equivalent in rank to the East Roman strategos or magister militum.
 * Poshtikbān Sālār: Head of the royal guard.
 * Erān anbāraghbad: Senior rank responsible for army supplies.
 * Stor Bezashk: Senior vet who looked after the cavalry elite's mounts.
 * Argbadh: Castellan, commander of a castle or fort.
 * Pāyygān Sālār: Chief of an infantry division.
 * Savārān Sardār: Head of a cavalry division.
 * Gond Sālār: Commander of a gond division.
 * Sardar: Brigadier General

Cavalry
The backbone of the Spâh in the Sassanid era was its heavy armoured cavalry, known since Classical antiquity in the west as Cataphracts. This was made up of noblemen who underwent extensive exercises in warfare and military manoeuvres through military training, gaining discipline and becoming true soldiers. Within the Sassanid military, the cavalry was the most influential element, and Sassanid cavalry tactics were adopted by the Romans, Arabs, and Turks. Their weaponry, battle tactics, tamgas, medallions, court customs, and costumes greatly influenced their Romano-Byzantine neighbours. The Romans had long contended against opponents who fielded heavy cavalry, notably the Sarmatians and the Parthians, and the recurrent wars with the Sassanids were an important factor in the Roman turn to new military organizations and battlefield tactics that centered around the use of heavy cavalry in the 3rd and 4th centuries. The Romans called these newly formed units clibanarii; It is said that the word clibanarii is derived from Persian word grivpanvar or griva-pana-vara meaning neck-guard wearer. Another, more direct and often quoted, etymology is the Greek word ho klibanos, which refers to a covered pot in which bread was baked or a small oven; perhaps a joking reference to the one-piece mask helmets they wore. The Roman term appears for the first time in the vita Alexandri Severi (56.5) in the Historia Augusta, a work from the very end of the 4th century AD.

Shapur II (r. 309–379) further reformed the army by adopting heavier and more effective cavalry. These mounted units were clad in thick iron plates which covered their entire body. This made them look very much like moving iron statues. Some were armed with a lance and some with a sword and/or mace. Depictions of aforementioned cavalry still survive, with one of the best preserved ones being a rock relief at Taq-e Bostan where Khosrau II is seen riding his favourite horse, Shabdiz.

The fighting equipment of the heavily armed Sassanid horsemen were:
 * Clibanarii/Cataphract cavalry: helmet, hauberk (Pahlavi griwban), breastplate, mail, gauntlet (Pahlavi abdast), girdle, thigh-guards (Pahlavi ran-ban) sword, mace, bowcase with two bows and two bowstrings, quiver with 30 arrows, two extra bowstrings, and horse armour (zen-abzar).

The heavy cavalry was complemented by lighter cavalry, which were not made up of Sassanids, but were recruited from among their allies and supplemented by mercenary troops. Albani, Hephthalites, Kushans and the Khazars were the main suppliers of this light armored cavalry. They were an essential part of the Spâh because of their endurance and speed on the battlefield.

It is possible that the mainly light cavalry were intended for the battles with the central Asiatic tribes, while the more heavy cavalry were used in encounters with Rome.

In short, there were the following classes of mobile cavalry troops:
 * Persian imperial guard (Zhayedan)
 * War elephants
 * Light cavalry: primarily horse-archers
 * Cataphract /Clibanarii cavalry: Heavy shock cavalry armed with lances, swords and maces (also known as Savārān cavalry)

War elephants
Both types of cavalry units were supported by war elephants and foot archers who showered the enemy with storms of arrows. The elephant corps held the first position. It was recruited from India, but was at no time very numerous. Great store was set by it; and in some of the earlier battles against the Arabs the victory was regarded as gained mainly by this arm of the service. It acted with best effect in an open and level district; but the value put upon it was such that, however rough, mountainous, and woody the country into which the Persian arms penetrated, the elephant always accompanied the march of the Persian troops, and care was taken to make roads by which it could travel. The elephant corps was under a special chief, known as the Zend−hapet, or "Commander of the Indians," either because the beasts came from that country, or because they were managed by natives of Hindustan. These giant beasts acted as walking towers on battlefields and caused panic and disorder in enemy ranks, creating openings in the lines that cavalry could take advantage of.

Infantry
The infantry were mostly lightly armed spearmen, who, like their Achaemenid ancestors, were usually levied troops of little fighting ability. Procopius of Caesarea famously derided them as "a crowd of pitiable peasants who come into battle for no other purpose than to dig through walls and to despoil the slain and in general to serve the soldiers [i.e. the cavalrymen]". In some battles however, heavy infantry was deployed. These were well-paid, heavily armoured infantry (carrying sword and javelin). The Daylam provinces of the empire in particular were famous for providing high-quality foot soldiers.

The archers formed the elite of the Persian infantry. They were trained to deliver their arrows with extreme rapidity, and with an aim that was almost unerring. The huge wattled shields, adopted by the Achaemenid Persians from the Assyrians (called spara by the Achaemenids), still remained in use; and from behind a row of these, rested upon the ground and forming a sort of loop−holed wall, the Sassanid bowmen shot their weapons with great effect; nor was it until their store of arrows was exhausted that the Romans, ordinarily, felt themselves upon even terms with their enemy. Sometimes the archers, instead of thus fighting in line, were intermixed with the heavy horse, with which it was not difficult for them to keep pace. They galled the foe with their constant discharges from between the ranks of the horsemen, remaining themselves in comparative security, as the legions rarely ventured to charge the Persian mailed cavalry. If they were forced to retreat, they still shot backwards as they fled; and it was a proverbial saying with the Romans that they were then especially formidable. Infantry was divided into the following types:
 * Daylami: mercenary heavy infantry
 * Paighan: peasant levies armed with spears and large wicker shields
 * Kamandaran: archers
 * Light ranged troops, such as Kurdish javelin-throwers

Siege weapons
The Sasanians had organized and efficient methods of siege warfare for conquering walled towns. First of all, we know they would mine the walls of besieged fortifications, as such a tunnel containing the body of a Sasanian soldier has been discovered underneath the walls of Roman Dura Europos. Their siege machinery included crossbows, catapults and battering rams, but they also had excellent defensive tactics for their fortifications, such as methods for using and countering catapults, for countering mining, for throwing stones or pouring boiling liquid on the attackers or by hurling fire brands and blazing missiles. In the fourth century CE, the Persians still used moving armoured siege towers, in order to strafe the battlements with artillery and to allow their soldiers to climb over them. In the sixhth century however, Procopius and Agathias no longer mention such towers, perhaps because at that time wheeled vehicles had almost entirely disappeared from the Middle East (Bulliet The Camel and the Wheel 1975). Instead of siege towers, Sasanian besiegers would now build a high siege mound, placing their artillery on its summit to target the defenders on the walls below. Like the Romans, the Sasanians also adopted the perrier or traction-trebuchet originating in the Far East, the forerunner of the later counterweight-trebuchet. They protected their sappers and soldiers with earthworks, shelters and mantlets.


 * Crossbow (Pahlavi çarx, NP charkh or charkh kamān Steingass 391. In the Middle East, this weapon was only used in sieges)
 * Catapult NP kamān-i charkh, kamān-i gāv ("ox-bow") Steingass 1047, the latter name suggesting that this second type of catapult was not drawn with a ratchet but with the help of a large and strong domestic animal like an ox. Such weapons are known to have been used in China.
 * Battering ram
 * Siege tower Ammianus Marcellinus 19.5.1, 19.7.2
 * Siege mound Procopius 1.7.17, 2.26.25-9
 * Perrier Bernard Lewis (ed.) Islam from the Prophet of Muhammad to the Capture of Constantinople (NY 1987) I.215: In a rather symbolic discussion between Arabs and Persians, written by Al-Jahiz, the Arabs are denounced for not knowing the ratila (Arabic for a catapult, though ziyar seems to have been more usual Hugh Kennedy The Armies of the Caliphs 113; C. Cahen “Un traité d’armurerie composé pour Saladin” Bulletin d’etudes orientales 12(1947-8) 133), the arrada and the manjaniq (Arabic for a small perrier operated by a few persons or even a single person (the pole-framed trebuchet) and a large perrier operated by up to 400 people respectively (the trestle-framed trebuchet)) or any other siege machinery, suggesting all these machines were already known to the pre-Islamic Persians. Pahlavi mangenik, derived from Greek manganikon, or koshkanjir NP Steingass 1033, 1062 kashkanjīr
 * Earth works, shelters, mantlets Ammianus Marcellinus 19.5.1, 7.3

Azadan nobility
This class of nobility was first formed in Parthian times, and was carried over into the Sassanid state, where they were a force to be reckoned with. They accompanied the king in the wars and displayed great courage and discipline. They are clearly the forerunners and founders of the "Knights" of later Arab history. The Aztan (Azadan, آزادان, "freemen") jealously guarded their status as descendants of the ancient Aryan conquerors and rulers of the mass of originally non-Aryan peasantry. These Azatan formed a numerous minor aristocracy of lower-ranking administrators, mostly living on their small estates and providing the cavalry backbone of Sassanid army. Most prestigious among them were the armoured "Asvaran" اسوران who normally decided the outcome of a battle.

Despite their downfall in the 7th century AD, the legacy of the Savaran endured in the Caucasus, India and the Muslim world. It was the elite cavalry of Sassanid Persia, who were the forerunners of the later Arabian Faris, the Caucasian horsemen, the Indian Sowar (derived from Persian Savar), and the Turkish Tarkhans.

The amount of money involved in maintaining a warrior of the Asavaran (Azatan) knightly caste required a small estate, and the Asavaran knightly caste received that from the throne, and in return, were the throne's most notable defenders in time of war.