Legions of Trajans Dacian wars

[diegis]

But do any of these authors provide references for their amazing totals? Cassius Dio - the main source for the Dacian wars - gives no estimate of the size of Trajan's army. I can't help but think that these extraordinary figures are inflated - perhaps they assume that every legion epigraphically attested in the region participated in the campaign, whereas in fact they may have just sent a vexillation, or even some veteran colonists in later years?

I think numbers are estimative, ofcourse, and come from legions attested in the region at that time, auxiliars (which i suppose was about equal or close in number with legionars) and irregular troops rised just for this wars (as Germanic ones depicted on Column for ex).
Beside Schmitz and Strobel numbers (175,000 Roman soldiers deployed in the battle area), Romanian authors give usualy (from what i read) about 150,000 Roman soldiers and Dacians varying from 40,000 to 100,000, again, just an estimation, Schmitz give for Dacians a potential number up to 250,000, thus not all up to be deployed on a single area or battle or all at once, but i think this number is exagerated.

I saw for Roman Army numbers even like 200,000 for the second war, when Roman Army advanced on 3 or 4 fronts in Dacia (and as low as 20,000 for Dacians in the second war). Unfortunately for Dacians numbers are even (much) less possible source then for Roman ones, and we can just speculate, thats why the range is so big.

The was a British vexillation operating on the continent in the 80s, but it was probably used in Domitian's wars on the Rhine. It's unlikely that this same group of men then moved to the Danube and were still there 20 years later. The 'Mauretanian detachment' presumably refers to Vellius Rufus's vexillation command in Domitian's Sarmatian war - Rufus had been Tribune of the Urban Cohorts at Carthage and fought in Mauretania, but there's no evidence that (as some have suggested) he actually brought troops from Africa to fight on the Danube. II Adiutrix was indeed brought from Britain by Domitian, though, and remained on the Danube long afterwards. Do the 'troops from Syria' refer to the vexillation of VI Ferrata I mentioned above?

I read some info from several authors about troops took from Britania and Germania (see as well the above post of Spurius Papirius Cursor), and about those from Mauretania for ex. they apear on Trajan Column (mauretan cavalry which was lead by Lusius Quietus). I think syrian archers are depicted too, or is just about that legion was mentioned before, dont know exactly. There are even slingers depicted there, germanic mercenaries armed with clubs, lots of diferent troops

Various bits of evidence suggest that a large force was concentrated in Upper Pannonia at the end of Domitian's reign - possibly for a putative third war against the Sarmatians and Suebi. The only units known are auxiliaries though.

From what i know Domitian managed to defeat Marcomani and Sarmatians wasnt any such threat to require any big concentration of troops. I think only real danger was Dacians. In fact i read (dont remember exactly the author now) that first defeat of Domitian by Marcomani and Quadi come because he keep a large bulk of its troops in Moesia, fearing of another Dacian surprise attack, and he attacked the Marcomani with a smaller army.

In fact Domitian problems with Marcomani comes from the fact he wanted to punish them, not because they attacked Romans or so. I think Dio Cassius said that Domitian wanted to punish them because they didnt join the Romans in their fight with Dacians (Marcomani was Roman clients/vassals at that time). Marcomanii even send 2 peace requests, but Domitian rejected them and even killed the messengers from the second envoy

Romans probably suffered already some great losses against Dacians (as mentioned by Orosius) and later was forced to pay even a tribute to Dacians and Decebalus, so is possible Roman authors to try cover such humiliations for the Empire (for ex. after peace was signed Roman standard and war machines captured by Dacians was kept by Decebalus, as well most of war prisoners, Romans paid large sums of money and send lots of engineers and military instructors to work for Decebalus, and allowed Dacian merchants to sell free their stuff in the empire) and dont talk about troops involved or details about battles, and i saw hypoteses that one of the main reasons for Domitian assasination was because of problems with Dacians and how the Empire come from that

Orosius is discussing Domitian's Dacian war in the piece you excerpted. His details elsewhere are rather faulty (did Claudius really conquer the Orkneys?), so even if he did estimate the size of Trajan's army - which he didn't - we should be sceptical.

From what i read and saw, apparently Romans used a large force, many scholars agree it was the largest used against a foreign enemy so i incline to believe it was around those numbers mentioned previously. Think just at the engineering features, as dig a secondary channel to drove a big part of Danube (which is second river of Europe, after Volga, and i think is in top 15 rivers in the world as water volume) from its main course and build the Trajan bridge (the biggest in the world for a millenium) and rebuild and reinforce in stone all fortresses in Moesia.