So first Caesar would have seen a large array of well-equipped men on sturdy chargers. These were the heavy cavalry, later known as cataphracts. They were as renowned as any Byzantine troops. They wore steel caps, and on each cap was a crest showing the colors of that bandon, or horse regiment. They also wore long mail shirts, steel gauntlets, steel shoes, and sometimes a light surcoat. Even the horses, at least those of the officers and the men in the front rank, had steel head armor and breastplates. For weapons, each man had a broadsword, a dagger, a bow and a quiver of arrows, and a long lance with a banderole, also in the bandon colors. They could charge like knights, or by acting as bowmen, they could fight a distant enemy.
Then Caesar would have seen the light troopers, or trapezidae. These too were cavalry, but they were the light cavalry. They did carry shields, but for body armor they wore only a cuirass of very light mail or horn. For weapons, they had only a lance and a sword.
There was still infantry in the Byzantine army, but it was now pretty unimportant. It was used mostly for holding ground which the cavalry had won. But even the infantry was divided into two groups. The heavy infantry were about as well armored as the cataphracts. For weapons, they carried a short, heavy battle ax and a dagger. They could stand off a barbarian cavalry charge. The light infantry wore no armor, but carried long-range bows. The Byzantine method of fighting was something like the German blitzkrieg, with cavalry taking the place of swiftly moving tanks and the foot soldiers following behind.
The Byzantines did much more than change their army into something swift and moving, however. They did more than divide the old clumsy legion into smaller units almost like our modern regiments, battalions, companies, and platoons. They spent a lot of time thinking about the whole business of fighting and may even have been the inventors of carefully planned strategy. They would not have been at all surprised at our modern war colleges where even generals are taught in the classroom what to do on the field of battle.
As a matter of fact, at least three Byzantine emperors wrote very good books on the art of war. These books included much more than just how to equip and drill an army. They also told the general exactly how he should fight his battles, and they emphasized that he must have a different kind of warfare for each different kind of foe.
The Franks, for example—and by the Franks, the Byzantines meant German and north Italian peoples quite as much as French and Normans—believe, said the books, that a retreat under any circumstances is dishonorable. Better die than show your back to the enemy. They are also very careless about outposts and scouts. So if you are fighting the Franks, you should try to trap them in a place where they will be at a disadvantage. Then you can annihilate them.
With the Turks—and by the Turks, the Byzantines also meant the Hungarians, the Patzinaks, and all the people of the Asiatic steppes—it is another matter, the books continued. They are light horsemen who carry bow and arrow as well as javelin and scimitar. They are hard to surprise because they always post mounted sentinels. Also you must be careful if you pursue them, for they don’t stay defeated but rally quickly. However, the heavy Byzantine cataphracts can ride them down and cut them to pieces. They are supposed to do so. And the Turks do not dare attack the Byzantine infantry because of its strong and powerful bows.
The Slavs, on the other hand, are only dangerous when they are led by Bulgarian khagans or by viking princes, and even then they are only really dangerous when they are in the hills. The thing to do, said the strategy books, is to lure them to the plains in hope of plunder. And then destroy them.
But the really difficult enemy faced by the Byzantines were the newly risen Arabs, or Saracens.
These wild sheiks from the desert were fanatically brave, for Mohammed had taught them that the easiest way to get to heaven was to die killing the unbeliever. Their numbers were limitless, for after they had conquered Egypt and Syria they drew into their ranks every discontented person in the Middle East. Once a year they poured, like a horde of locusts, through the gates of the Taurus Mountains into what today is southern Turkey. Nothing, including the Byzantine army, could stop them.