I feel pretty certain that nowadays we would point to the advent of Islam as the most important development of the movement that Muhammad began in Mecca and Medina in the first part of the 7th century. However, to contemporary observers in the period immediately following his death, it must have seemed like the military and political changes his career wrought were far more significant than the theological ones. I mean, even in the lands the early Arab/Muslim armies conquered, Islam remained a minority religion (at least outside the Arab community) for at least a generation or two after the conquests. But those conquests themselves, holy crap. The problem with talking about them from a historical standpoint is that the earliest comprehensive writings about them don’t show up for a century or more after their completion, and they tend to rely on a lot of topoi (tropes), by which I mean you see a lot of similarities in accounts of different engagements that lead you to believe the writers are simply filling in the blanks in a story formula rather than accurately describing what happened. But there are some things we know about the army that made those conquests.
Within two decades after Muhammad’s death, the army he first began crafting at Medina had severed the (Eastern) Roman Empire from most of its territory and had wiped the Sasanian Persian Empire from the map. Think about that–an army headquartered in a small oasis community in a part of the world that was so insignificant that neither the Romans nor the Persians ever bothered conquering it suddenly came swarming out of its homeland, destroyed one of the region’s great powers, and slashed the other in half. Imagine if, I don’t know, Bolivia or Ethiopia or Cambodia had fought simultaneous wars in the 1960s against the US and USSR…and won both of them. The entire geopolitical order would have been upended just a bit. It wasn’t possible for anybody to upend the entire geopolitical order in the seventh century–India was more or less still there (although the early Muslims conquered a fair chunk of it), China was too far away to be affected (although its designs on Central Asian hegemony were squashed), and it would be another 800 years before people in the Mediterranean region even knew about the Americas–but the change in the region from North Africa to the Indus valley was massive and sudden.
Although very little is really known for sure about Arabian society before Muhammad, I think we can reasonably conclude from the amazing military success they had in very short order that the men who came to follow Muhammad already had some idea how to fight before they joined his movement. And that makes sense. Nomadic societies, by which I mean the nomads themselves as well as the settled people living on the nomadic frontier, historically tended to be pretty well-armed and well-trained. Nomadic groups engaged in seasonal migrations other kinds of herd movements that aren’t all that dissimilar from the kinds of movements an army in the field has to make, and they tended to be trained in how to use weaponry, both to defend against competing nomadic groups and in order to make the occasional raid on a city or town. People living in those cities and towns, not coincidentally, also stocked up on weapons and learned how to use them, in order to (hopefully) fend off those raids.
Surviving pre-Islamic Arabic poetry suggests a martial culture that was built around champion vs. champion fights, and early Islamic sources also describe battles between Muhammad’s men and their Meccan enemies as having begun with one-on-one champion battles before the main fighting began (Muhammad’s champions win most/all of these, naturally). So it’s possible that one of Muhammad’s many innovations was turning his Arab followers into a real combined army, one that was organized around infantry fighting in formation, that used skirmishers like javelin throwers and archers to soften up the enemy, and that used cavalry to probe the enemy’s flanks and pounce on enemy infantry once it had been routed. This achievement is all the more remarkable when you consider that he was stitching this army together out of a mishmash of tribes that couldn’t possibly have had any experience fighting alongside one another. In this, obviously, the Qurʾan played an incredibly important role. Whatever the modern implications of jihad are, Qurʾanic passages exhorting war against unbelievers (there are legitimate questions about when such war was justified and who exactly counted as “unbelievers”) were a powerful unifying force for the early Arab armies.
The army’s organization and weaponry was probably patterned on the Roman/Byzantine example, although the Arabs had two early disadvantages: they didn’t have enough horses to adequately supply a cavalry wing, and they had little idea how to wage siege warfare. Both of these were resolved in time–more conquests meant acquiring more horses in tribute, as well as more land on which to raise more horses, and assimilating the machines (trebuchets were the most common, though they were more commonly used against armies in the field) and techniques of capturing cities. But the early sources describe a lot of cities falling to the Muslims the way Jericho falls to the Israelites in the Book of Joshua (leaving aside the bit about the trumpets and the walls): because someone inside the city is convinced to aid the righteous attackers. That’s the kind of trope chroniclers might use to make it clear that the new faith, not its army, was responsible for the conquests, but it’s also the kind of tactic you might see from an army that really has no way of taking a well-fortified city except by turning–whether with faith or with cash–somebody on the inside. The chronicles don’t really mention the Arabs using siege engines until conquests that took place in the 8th century, though that doesn’t mean that they weren’t used before that.
One asset the early Arab armies did have in abundance was camels. These weren’t so great in a cavalry fight, but they were incredible both as pack animals and as mounts for the infantry when moving between battles. The speed with which the Arabs were able to move, owing to their mounted infantry, was one of their biggest advantages, because it allowed them more often than not to control where battles were fought and to establish position on the field before their enemies could arrive. Another asset was the degree of organization that underpinned the military from very early on, thanks to the second caliph, Umar b. al-Khattab (d. 644). Umar instituted the diwan, or registry (diwan al-jund, “army registry,” if you must), which was nothing much more sophisticated than a list of all the military men in the empire along with records of their service, in order to ensure that they (or their surviving family members) were each paid what they were owed (soldiers who’d served longer were, obviously, due more money). In a sense the payments functioned like pensions; soldiers and their families were paid for their past service in campaigns. Soldiers were also compensated with provisions (food, clothing, etc.) and with grants of settlements (qataʾiʿ) in garrison cities, or occasionally with larger grants of land (iqtaʿ), though this system became much more complex and pervasive later on. The diwan worked exceptionally well in terms of ordering military affairs–so well, in fact, that it spawned a whole host of other diwans covering taxation, correspondence, charitable disbursements, and so on. The bureaucratization of the army led to the bureaucratization of the whole empire, and in fact the word diwan began to refer to a “department” rather than simply a “register.”
Still another asset working in the favor of the Arab conquerors was great generalship, and in particular the great generalship of one man, Khalid b. al-Walid (d. 642). We’ve talked about Khalid’s great abilities as a commander in previous entries, but he deserves some mention in a discussion of the early Arab military. An early opponent of Muhammad’s teachings who led the Meccan armies to victory at the Battle of Uhud in 625, Khalid eventually joined Muhammad’s movement and won one of the most important engagements of the 632-633 Ridda Wars. Later he commanded Arab armies that defeated vastly larger Sasanian and Byzantine forces in Iraq and Syria, respectively. His army’s six day forced march from Iraq to Syria in 634 is the stuff of legend, even though we don’t really have a great handle on what really happened other than that he pulled it off (successfully enough that his army besieged and conquered Damascus shortly afterward). Khalid wasn’t the only capable Arab commander, either. For example, there was Amr b. al-As (d. 664), the conqueror of Egypt, who had a background similar to Khalid’s (early opposition to Muhammad, meritorious service in the Ridda Wars). He commanded an army in Syria before being sent further west where, against heavy odds and with remarkable speed, he conquered Egypt (639-641) for the caliphate. After a stint as the deputy to Muʿawiyah, the governor of Syria who later became caliph, Amr was able to wrangle an appointment as governor of Egypt, where he’s credited with helping to restore and preserve the Coptic Church.
Getting a handle on the size of these early armies is very difficult. The earliest surviving sources for the conquests were still written decades after the fact, and anyway even eyewitness accounts from that long ago are notoriously unreliable when it comes to troop counts. People writing from the perspective of one side or the other always have a tendency to exaggerate the size of the enemy’s forces and minimize their own side’s strength, either to make a victory seem more heroic or to excuse a defeat. The modern consensus seems to be that the Arabs had about 30,000 men (20,000-40,000 is the range usually given) operating in Syria at the same time, though these forces were usually divided among a number of active armies. They had considerably smaller forces in Iraq (12,000 at most) and Egypt (maybe 4000 before reinforcements were sent).
Accounts of the battles of the conquest suggest that these armies were organized into units based on tribal affiliation (each tribe carrying its own battle standard), but they also talk about recognizable organizational units like right and left flanks, rear guard, vanguard, etc. So those tribal units were probably grouped into larger tactical units, but also broken up by military specialty (if a tribe had some cavalry it would fight with the other cavalry, not with that tribe’s infantry). If this is accurate there’s a pretty sound reason for it; if/when a battle descended into chaos, and those tactical units lost their cohesion, the tribal units within them could be counted on to rally around their banner and keep fighting hard to protect their kinsmen. While most of these forces were Arab, some local fighters joined up and/or defected (everybody loves a winner); these were called mawali (clients) because, in order to fit in to the established organizational framework, they had to become affiliates (clients) of a particular Arab tribe). You can think of them as “coverts” if you like, but Islam wasn’t fully formed enough during the conquests for that term to really mean much. Many mawali were also slaves, POWs who were freed in exchange for their service, and here we can see the roots of the slave soldiery that really became predominant by the mid-9th century.
Once the conquests were completed, many of these soldiers settled in the regions they conquered, either in new “garrison cities” (amsar) created for them in Iraq and Egypt (the Iraqi cities of Kufa and Basra were founded this way, and Fustat, in Egypt, isn’t its own city anymore but is part of the historical section of Cairo), or in already existing towns and cities as tended to be the case in Syria. There they functioned more or less as tribal levies, with the local appointed commander (amir) responsible for collecting them back into service to go on campaign or for defensive purposes. Amirs would have a standing police (shurta) and bodyguard (haras) units under them, which were very powerful for a time because they were the only standing military units in the empire–as the army became more professionalized the prestige of these institutions declined. Under the caliph Abd al-Malik (d. 705) we see the beginnings of a standing army (along with the disappearance of military units based on tribe), and the payments registered on the diwan stopped resembling pensions (payment for past service) and began looking more like salaries (payment for current service). Gradually military service, rather than chummy and/or familial ties to the caliphal court, began to become the surest path to high political appointment. The standing army grew through the caliphal period, and under the Abbasids it was probably around 100,000 strong, all wholly or at least semi-professional (Kennedy, in When Baghdad Ruled the Muslim World, suggests that they were all paid a regular salary but many probably took additional work on the side, or ran their own businesses). Under the Abbasids the army’s officer (qaʾid) class became professionalized, where previously officer appointments had been temporary things for a particular battle or campaign.
Let’s talk weapons and armor, which soldiers were, at least during the early conquests, expected to provide for themselves (so the quality of any soldier’s arms would have varied based on what he could afford or what he could loot in battle). We know the infantry (the core of the army) relied on iron spears and swords (straight stabbing swords at first; scimitars were a later import from the east), cloth (or maybe chain mail for those few who captured or could afford it) armor, helmets (leather or metal) or mail hoods, and leather shields. Javelins and bows were used as skirmishing weapons, and the Abbasids also employed men using flame weapons (possibly fueled by Greek Fire or perhaps just simple crude oil). Cavalry fighting made heavy use of lances (though swords or maces would have also been carried as secondary weapons). Umayyad and Abbasid cavalry also were among the first cavalry soldiers whose use of the stirrup can be historically attested. This probably increased their effectiveness, and may have allowed mounted archery to become a viable military technique by making it easier to fire a bow from horseback. Under the Umayyads (c. 661-750), whose Syrian Arab forces were the backbone of the army, the cavalry began to divide into light and heavy units, with the unarmored light horsemen used for scouting and the well-armored heavy units (horse armor may have come into use around this time) used as shock troops. This, again, reflects an adoption of Byzantine and Persian equipment and tactics, and while it may seem odd that the conquerors adopted the military techniques of the conquered, it was around this time when the Arabs began to make contact with Central Asian Turkic horse archers and so they adopted the same armor that the Persians had used when dealing with that particular opponent.
With the rise of the Abbasids (c. 750), Arab soldiers began to be supplanted as the core of the army, first by Iranian Khurasani troops and later by Turkic slave soldiers, both of which placed far more emphasis on cavalry warfare than the Arabs had. The Khurasanis fought as heavy cavalry, in full armor and wielding swords, clubs, and axes, and even their infantry were mounted for transportation purposes and were trained to fight from horseback (using spears) if the situation required it. The Turks brought with them the art of mounted archery, which was so devastating as a technique that it fundamentally changed caliphal warfare. I don’t want to get too deep into the rise of the Turkic slave soldier because we’re not there yet in the history and it represented a real social change for the caliphate that we’ll see unfold over a long period of time.
If we move west, we need to account for another ethnic group with its own military traditions: the Berbers. They don’t seem to have been particularly formidable when the Arabs began invading North Africa–lightly armed with swords, shields, and javelins, and not particularly sophisticated from a tactical standpoint–but they were quick to adopt the weapons and tactics of the Arabs, and by the time the first Muslim forces crossed into Iberia in the early 8th century the Berbers were as much a key to their strength as the Arabs. The two big differences in the west were the importance of naval warfare and the use of frontier fortifications, called ribats. Where naval capability didn’t become a real point of emphasis for Muslims in the eastern Mediterranean for a few centuries, in the western Mediterranean it was crucial to early expansion into Iberia (8th century) and Sicily (9th century).
The ribat fortifications, which dotted North Africa and were manned by volunteer fighters, were built mostly to defend caravan routes from marauding tribes (not all the Berber peoples were immediately receptive to the early Islam brought by the Arabs). These may have been similar to the “desert castles” built by the Umayyads in various places in Syria in the late 7th and early 8th centuries–although it’s not entirely clear what the desert castles were for, protecting merchant traffic was probably one of their purposes. The reason I mention them now is because their highly motivated defenders became fertile ground for traveling Sufi scholars looking for students. One group of ribat defenders/students eventually grew into a whole movement, the al-Murabitun (“ribat occupiers”) or Almoravids, that came to rule most of Andalusia and Morocco in the 11th and 12th centuries. So we’ll be coming to them later.
This is not to say that fortifications weren’t important in the east. Fortifications were important, from simple ditches to wooden forts to brick structures to outright castles, though many of the most impressive “early Muslim” fortifications were the Roman-built walls surrounding cities that were conquered by the Arabs, like Damascus. Newly build cities, like Kufa and Basra, interestingly, often weren’t constructed with walls initially but had them added to the city after some kind of attack made them a necessity. Then there are the aforementioned Umayyad “desert castles,” or qusur (singular qasr), about which nobody really knows much for certain. They were probably multi-use facilities, meant both as defense against raids from nomads and/or militant groups like the Kharijites and as way-stations where merchants could stop, water their animals, and rest before continuing their journey to whatever city was their next stop.
Hopefully this was as much as (or more than) you ever wanted to know about the early Arab/caliphal armies. I went into this one kind of open-ended so if there’s more that anybody would like to see here, suggest it in the comments and I’ll see what I can do.
NEXT: A couple of posts on high society are in order. Next time we’ll look at early Islamic philosophy, and then after that we’ll look at early literature. Both of these will take us a little past where we are in the history, but I think we’ll manage. Then we’ll cover the socio-political makeup of the early caliphate before getting back to the historical narrative.
I already cited two books by Hugh Kennedy, The Early Arab Conquests and When Baghdad Ruled the Muslim World, but I used a third book of his far more than either of those in writing this: The Armies of the Caliphs.
Fred Donner’s Early Islamic Conquests includes a section on military matters that is very useful.
To the extent that much is known about Umayyad military reforms, G.R. Hawting’s The First Dynasty of Islam was helpful.
Patricia Crone’s Slaves on Horses: The Evolution of the Islamic Polity has important things to say on military and tribal organization.
Osprey Publishing has this series of very short books called “Men-at-Arms” that are kind of silly little things, but they’re written by serious military historians and if you’re looking for a discussion of things like arms and armaments they generally go into much greater detail than most history books. There are two of these by David Nicolle that deal with the pre-slave soldier period: The Armies of Islam, 7th-11th Centuries and The Moors: The Islamic West 7th-15th Centuries AD.