Mongol Empire vs Byzantine Empire

[Pablo Sanchez]

How exactly did the Empire levy and equip troops in this era? I know that from the reign of Heraclius forward the territories were organized into feudal themes which had to supply X number of troops, but how did they do it in the Justinian era?

Justinian was still proto-Roman. Cataphracts were landed nobility from Asia Minor, and infantry were usually farmers or unemployed city folk who volunteered. I believe there were occasional infusions of better troops by other means, like levies of Isuarian hillmen or Bulgarian archers. They went to the theme system because it increased the number of quality troops they could levy.

EDIT:
Looking at the records, you really get a sense of a real manpower shortage. Belisarius stands out. To defend the capital city from the mob, he can only get a few thousand men. To attack Persia? Same story. Taking North Africa? 10-15 thousand men, more or less. Taking Italy? Shortchanged again. The last battle of his career, a life or death defense of Thrace from the Bulgarian hordes? A sparse assortment of local militia and palace guards.

Part of this was because he was too popular to risk a coup attempt, but it was also because there simply weren't troops available.

[The Dark]

The Byzantines have the leadership, skills, and tactics to win it, but they don't have the numbers. The Mongol attack will probably come from Persia, and will thus meet Byzantine armies first in Syria. Any armies that the Byzantines put in their way at this stage will be lost, because the Byzantines at best can muster 50,000 or so men, mainly infantry, and the Mongols can throw 120,000 or more horsemen. In the era we're talking about, there is enough forage in those areas to support a horse army of that size, and in fact the Muslim were able to overrun Egypt and Syria with little more than lots of horses and fanatical resolve.

The largest army I can ever find referenced for the Mongols is the 90,000-110,000 used by Chingis Khan to attack Samarkand in 1219. By comparison, the Byzantines had expeditionary forces of 20,000 under Narses and 15,000 under Belisarius at the same time, as well as having a mercenary force of 60,000 Avars just a few years later. Given that they already had the treaty with the Avars (but did not bring it into play) at the time of Belisarius, back around 600 AD, their army would have been at least 95,000.

Of course, this whole scenario is voided if the Mongols decide to play it really tricky and send half their army via the Persia-Syria road and the other half via the Ukraine-Bulgaria road. The Byzantines would then be outnumbered at two ends of the Empire, forcing them to disperse their forces, and just about everything except Constantinople would fall. I don't see any way for the Mongols to starve that city out, really. It's pretty much impossible to take the son-of-a-bitch without gunpowder artillery

If they try to get fancy and split their forces, then they'll probably outnumber one and be outnumbered by the allies of the Byzantines at the other. The Albanians, Bulgarians, Hungarians, and Avars would all fight to hold their territory against the hordes, and could most likely muster a total force nearly twice the size of the entire horde, given that the Avars sent an expeditionary force of 60,000.

[Pablo Sanchez]

The largest army I can ever find referenced for the Mongols is the 90,000-110,000 used by Chingis Khan to attack Samarkand in 1219. By comparison, the Byzantines had expeditionary forces of 20,000 under Narses and 15,000 under Belisarius at the same time, as well as having a mercenary force of 60,000 Avars just a few years later. Given that they already had the treaty with the Avars (but did not bring it into play) at the time of Belisarius, back around 600 AD, their army would have been at least 95,000.

Get your facts straight. The time of Belisarius and Jusitinian is closer to 530-550 AD, and the Avars are the enemies of the Empire at this point in history.