Vespasian\'s Auxiliaries

[Rumo]

Duncan, I guess you quote from Roman Army Studies, vol. I, while I have the ANRW version of this article (vol. II.3, p. 202-231). On numeri I have also Pat Southern's "The Numeri of the Roman Imperial Army" in Britannia, 20/1989, 81-140. According to her "Speidel's article on ethnic troops filled the gap to a certain extent" and she quotes it quite often.

Speidel (contra Mommsen): "the term numerus in a military context means no more than 'unit' - it is not a technical term for a special class of units and its usage in the latter sense by scholars, misleading as it is, should be discontinued" (p. 206). Of ethnic units he adds they "might differ far more from each other than has been assumed up to now" (p. 207) which is qualified by Southern as "probably the most useful statement about numeri that has ever been made" (p. 87-8). But she disagrees with Speidel's equation: ethnic units (numeri, vexillationes, etc) = nationes ("This is probably unfounded, and the nationes were probably quite separate from the numeri"). On this point I agree with you, Speidel's argument based on Hyginus is actually a conjecture which is not particularly persuasive.
However I don't understand why you claim "no connection whatsoever" between late Empire equites and vexillationes and Speidel's ethnic units. The latter is his own construct about barbarians in Roman army. Caracalla's German guard was also "ethnic", also "unit", was it not? As for the gradual romanization of barbarians within the Empire (and of ethnic units in particular), the outline at page 203 (with a brief bibliography in footnotes) seems enough for the scope of this article.

As such I still disagree with "special pleading from limited evidence and selective citation of evidence to suit his theory" verdict. Especially about recruitment and deployment, as Speidel's evidence is significantly more consistent than Brittones at Odenwald.

By choosing to quote Speidel I see I placed an unjustified burden on his shoulders, so here're few more:

P. A. Brunt, "Conscription and Volunteering in the Roman Imperial Army" in Scripta Classica Israelica, I, 1974, 90-115. See p. 104-106 about recruitment and some tendencies in deployment: "Auxiliary units were normally posted to regions other than those where they had been raised" and "Thracians, enlisted in large numbers, are found in alae far distant from their homes; Britons and Dacians were apparently not used in their own country, to which it was therefore necessary to send men from other parts." Konrad Kraft's Zur Rekrutierung der Alen und Kohorten an Rhein und Donau (Bern, 1951), p. 43-68 is referenced in footnote but I don't have it to further search for quotes and eventually arguments.

David MacDonald, "A New Egyptian Diploma Fragment", ZPE 133/2000, 271-4. " By the second century, recruitment was largely local, but there were many exceptions, and Thracians in particular were sent to many units far from their home province." (in footnote several studies by Speidel, but not the one we've been discussing)

Dan Dana, op. cit, p. 167: "Ces Daces, comme les Thraces, les Bataves et les Bretons, réputés comme des «peuples guerriers », n'étaient pas employés dans leur pays. Toujours comme les Thraces, les Daces furent largement recrutés, et envoyés aux quatre coins de l'empire."

Interesting subject. It's my impression that a provincial garrison only changed during periods of warfare or annexation (there or elsewhere, by domino effect). But it would probably bear detailed study.

Probably, but at some point we'd expect the natives to show up consistently in the epigraphic record, replacing casualties or even entire units which moved elsewhere. They certainly do show up in many provinces but not in all of them, which calls for a supplementary explanation.

Again, an interesting phenomenon. Of course, if natives were banned from serving in their own province, we'd expect 0 Dacian names in Dacia! But, of course, as elsewhere, Roman units were recruiting locally.

I don't think any of these authors suggest a policy enforced without exceptions, but of tendencies, whatever the cause behind them.

Those ~60 Dacian "natives" were an optimistic (acknowledged to be so even by its proponents) estimation (I.I.Russu, "L'onomastique de la Dacie Romaine" in L'onomastique latine, Paris, 1977, p. 353-63): they have names which weren't Greek, Latin, Semitic, etc., some were Thracians and some just speculated to be (e.g. there are 8 or so named Mucianus and it was assumed their name is a Romanized Thracian one, cf. Mucatralis, Mucaporis). There are very few certain Dacian names in Dacia such as Decebalus Luci at Germisara - AE 1992, 1483 (a votive inscription).

Even if we admit an epigraphic presence of 2% native names in Dacia, this is unexpectedly small percentage (for example see András Mócsy, Gesellschaft und Romanisation in der römischen Provinz Moesia Superior, 1970, p. 193: 31% local names in Pannonia for 1st-2nd century, 7% for 3rd-4th and 13% in Upper Moesia for 1st-2nd century). I know there are methodological issues and biases but this difference becomes more problematic if we consider we know more Dacians (especially soldiers!) and Dacian names outside Dacia than in it.

[D B Campbell]

I stand by my critique of Speidel's paper, Drago?. His stated purpose is "to trace ... the rise of barbarian elite vexillationes through its successive stages from the beginning to the establishment of the Later Roman army" (p. 119 = 204). In my opinion, he has failed to do so, because such a development does not exist.

But the theme of Jona's thread was Vespasian's supposed policy that auxiliary units should not serve in their homeland. Speidel's contribution to this was to point out (in a rather controversial way :wink: ) that the special units usually known as "national numeri" (he prefers to rename them as "nationes") are only found far from their homeland. That is a useful observation. But still raises the question of whether this was a conscious decision to deport natives from Britain to Upper Germany, Palmyrenes to Dacia, Syrians to Africa, ... Or were newly-raised units, whatever their origin, simply deployed wherever required?

P. A. Brunt, ...: "Auxiliary units were normally posted to regions other than those where they had been raised" and "Thracians, enlisted in large numbers, are found in alae far distant from their homes; Britons and Dacians were apparently not used in their own country, to which it was therefore necessary to send men from other parts."
David MacDonald, "A New Egyptian Diploma Fragment", ZPE 133/2000, 271-4. " By the second century, recruitment was largely local, but there were many exceptions, and Thracians in particular were sent to many units far from their home province."
Dan Dana, op. cit, p. 167: "Ces Daces, comme les Thraces, les Bataves et les Bretons, réputés comme des «peuples guerriers », n'étaient pas employés dans leur pays. Toujours comme les Thraces, les Daces furent largement recrutés, et envoyés aux quatre coins de l'empire."

Likewise, I could quote many, many authors who say the same thing. (Safety in numbers?!) But what is their basis for claiming (e.g.) that auxiliary units (i.e. alae and cohortes) were "normally posted to regions other than those where they had been raised" (ooh, ugly sentence -- did Brunt really write that?!). What is normal? (Spanish units, anyone?) And, more importantly, what is Brunt implying? That this is accidental? Or that there was a policy?

Your quote from MacDonald is also accurate. We know that auxiliary units began recruiting locally, because onomastic evidence demonstrates it. "... but there were many exceptions" -- so this is his "get out" clause, in case anyone mentions Hamian archers. His citation of the Thracians is a red herring, too. Thrace was prime recruiting country, but required only a minuscule garrison. So by definition, large numbers of Thracians had to go far from their homeland! Similarly, Gauls are found all around the empire.

What we need is a Batavus serving in Lower Germany after Vespasian's supposed ban on Germans serving near their homeland. :wink:

[Rumo]

I stand by my critique of Speidel's paper, Drago?. His stated purpose is "to trace ... the rise of barbarian elite vexillationes through its successive stages from the beginning to the establishment of the Later Roman army" (p. 119 = 204). In my opinion, he has failed to do so, because such a development does not exist.

His stated purpose is "to trace, not comprehensively, but in examples, the rise of barbarian elite" (emphasis mine), and since his paper is mostly an array of mentions (almost all epigraphic, only few literary) and woven interpretations, I don't know what other type of "not comprehensive trace, in examples" would one have in mind? Please also note he doesn't actually claim late Empire vexillationes continue numeri (the former are repeatedly described as a "new" type of unit), he rather traces ethnic (or "ethnic") continuities (see his detailed section on Mauri) to show these (elite) ethnic units are not solely responsible for the barbarization of the army ("the progressive 'barbarization' of the army [...] is undeniable fact, but the blame for it cannot be laid squarely on the ethnic units as such", p. 203 but also check the last and conclusive section of the article).

Likewise, I could quote many, many authors who say the same thing. (Safety in numbers?!)

They do not say quite the same thing, however I actually quoted them mostly to move the focus off Speidel's article.

But what is their basis for claiming (e.g.) that auxiliary units (i.e. alae and cohortes) were "normally posted to regions other than those where they had been raised" (ooh, ugly sentence -- did Brunt really write that?!). What is normal? (Spanish units, anyone?) And, more importantly, what is Brunt implying? That this is accidental? Or that there was a policy?

I believe that it's not possible to fully understand a scholar's argumentation if one doesn't read the relevant bibliography. However it seems to me that Brunt alludes both to the elite status of these units ("new recruits were commonly obtained from the hinterland of their station or from other regions to which they were temporarily transferred, but exceptions still occurrred [...] for specialist units, wherever employed, recruits continued to be drawn from the lands where they had been raised", "in the earliest period Gallic and Spanish cavalary were so prized that they too had to be used extensively far from home") and as a policy against potentially rebellious natives ("The government had not yet to come to trust its subjects to defend their homelands. It is characteristic in 65 supplements for the Illyrian legions were to be raised in Narbonensis, Asia and Africa."). I assume the main evidence is an obvious discrepancy between the ethnic epithets of these units, the names and origin of the serving soldiers and their actual location.

Thrace was prime recruiting country, but required only a minuscule garrison. So by definition, large numbers of Thracians had to go far from their homeland! Similarly, Gauls are found all around the empire.

I guess to many (probably also to these scholars) it would make sense to deploy Thracians on Danube instead of Britain or Mauretania. Or Gauls on Rhine. Perhaps some were but also many were not.

What we need is a Batavus serving in Lower Germany after Vespasian's supposed ban on Germans serving near their homeland. :wink:

Like the existence of a law against thievery would be disproved by a theft

[D B Campbell]

Please also note he doesn't actually claim late Empire vexillationes continue numeri (the former are repeatedly described as a "new" type of unit), he rather traces ethnic (or "ethnic") continuities (see his detailed section on Mauri) to show these (elite) ethnic units are not solely responsible for the barbarization of the army.

So, a bit of a ramble, then. (But that's Speidel! :wink: And there are often some gems uncovered along the way.)

I believe that it's not possible to fully understand a scholar's argumentation if one doesn't read the relevant bibliography.

I don't want to become unduly argumentative, but surely an author's job is to explain what he believes, and why. We cannot assume that each reader will also read everything that precedes! (I don't happen to have Brunt to hand, so I was at a loss to follow up that strand of evidence. How many others are in the same position?)

... "in the earliest period Gallic and Spanish cavalary were so prized that they too had to be used extensively far from home" and as a policy against potentially rebellious natives.

But, again, these are the same suppositions that I am highlighting. I'm not saying that they are necessarily wrong. But I'd like to know where they stem from. If they are simply conjecture, then perhaps they are wrong.

Thrace was prime recruiting country, but required only a minuscule garrison. So by definition, large numbers of Thracians had to go far from their homeland! Similarly, Gauls are found all around the empire.

I guess to many (probably also to these scholars) it would make sense to deploy Thracians on Danube instead of Britain or Mauretania. Or Gauls on Rhine. Perhaps some were but also many were not.

Surely only if they are required there. If you have already organised your garrison of Moesia, and Britain happens to need some units, do you shuffle everyone along, so that recruits remain near their homelands? Or do you simply move the first available unit, no matter how far away it is? (I have not studied the phenomenon, but these are the questions that this thread has raised.)

What we need is a Batavus serving in Lower Germany after Vespasian's supposed ban on Germans serving near their homeland. :wink:

Like the existence of a law against thievery would be disproved by a theft

Not quite. :wink: It would be disproved by authorities condoning a theft, which is subtly different. (As you probably know, it seems that when someone signed up for the army, his background was meticulously checked: otherwise Pliny would not have known that he had some slaves illegally en route for military service. Likewise, if Vespasian ruled against Germans serving on the Rhine, woe betide the governor who signed them up!)

But thank you for debating these points with me, Drago? -- I am enjoying our discussion!

[Rumo]

Hello again, Duncan, and happy new year!


Despite my prolonged break, I also share your enthusiasm about this discussion, so here goes my first contribution to RAT in 2010:

I don't want to become unduly argumentative, but surely an author's job is to explain what he believes, and why. We cannot assume that each reader will also read everything that precedes! (I don't happen to have Brunt to hand, so I was at a loss to follow up that strand of evidence. How many others are in the same position?)

I do agree with you that this would be the ideal case. But at the same time there are some unavoidable constraints. I mentioned mostly short or medium-sized studies, often on a different topic. I guess an author wouldn't waste some of his precious time and space on an excursus of relatively little importance to his main argumentation and narrative. Also let's have in mind the purpose of the material. A study published in an academic journal, a study designed to add new arguments and hypotheses in an already developed historiographical trend might require the readers to be aware of some previous important contributions in the field. It's up to each of us how deep our investigations are, but as previously mentioned, I think a better understanding comes only with a rich bibliography summing various contributions from different interpretative angles and inherently making good use of the existing evidence.

For example, here is MacDonald's article in ZPE (unfortunately Dana's article is not freely available online, but through sites such as JStor). As it is only a 4 pages epigraphic note (including illustrations and footnotes), I don't think MacDonald owes to answer a why on a marginal comment such as on Thracians being sent far away from home; the short bibliography in the footnote is decent enough.

But, again, these are the same suppositions that I am highlighting. I'm not saying that they are necessarily wrong. But I'd like to know where they stem from. If they are simply conjecture, then perhaps they are wrong.

Brunt quotes mostly Kraft's Zur Recruitment for his statements on auxiliary units and G. Forni's Il Reclutamento delle Legioni da Augusto a Diocleziano (1953) for legions. In this case I can tell you the what-s and if you want to understand better the why-s, I guess you have to read Brunt's bibliography. For the statement you questioned the footnoted reference is Kraft, 26 ff.

Surely only if they are required there. If you have already organised your garrison of Moesia, and Britain happens to need some units, do you shuffle everyone along, so that recruits remain near their homelands? Or do you simply move the first available unit, no matter how far away it is? (I have not studied the phenomenon, but these are the questions that this thread has raised.)

One of the articles I happened to read in the past month is D. J. Knight's "The Movements of the Auxilia from Augustus to Hadrian" (published in ZPE 85/1991, p. 189-209), fortunately for this thread also available online.

It was a suprise to me to find in many cases a regular shuffle (Knight calls it "knock on effect", see p. 199, 206, 208). While the author admits this process is not yet proven "beyond doubt", the presented set of examples suggests long distance transfers of auxilaries is the exception, not the rule.

About the Batavian revolt (p. 195):

• After the suppression of the Batavian revolt, Vespasian initiated a new policy in the Rhineland. In pre-Flavian times local militias and alae and cohortes that were not fully integrated into the regular auxilia, were employed in Germania. This proved disastrous during the Batavian revolt, when such troops almost invariably sided with the rebels. Consequently, Vespasian organized these formations into regular units and transferred most of them to Britain, thereby removing a dangerous element from the Rhine.

I still don't know what is the hard evidence for this policy (here again we find the what, but not the why), but arguably the fact that Batavi, the Daci and other notoriously warlike tribes were initially deployed in auxiliary units further away from their homes it suggests avoidance of shuffling (without denying that a long distance transfer is not necessarily evidence for a troublesome 'nation'). Whether intentional (i.e. policy) or not, I guess it is still under debate.

Not quite. :wink: It would be disproved by authorities condoning a theft, which is subtly different. (As you probably know, it seems that when someone signed up for the army, his background was meticulously checked: otherwise Pliny would not have known that he had some slaves illegally en route for military service. Likewise, if Vespasian ruled against Germans serving on the Rhine, woe betide the governor who signed them up!)

Laws are made to be broken. Well, not really, but I hope you get the point.

I guess we can imagine many scenarios in which a high status person (including the emperor himself) allows an exception (we can call it corruption, whim, etc.), but also it can be the case of a legal subterfuge. A perfect world is an ungranted (though sometimes useful) assumption in almost every study :wink:

[Peroni]

What we need is a Batavus serving in Lower Germany after Vespasian's supposed ban on Germans serving near their homeland.

Here you go Duncan. Gaverius a cavalryman..


RMD-04, 00216
Germania inferior (Elst )
[Imp(erator) Caesar divi Nervae f(ilius) Nerva Traianus Aug(ustus) Germ(anicus) pont(ifex) maxim(us) trib(unicia) potest(ate) co(n)s(ul) II equitibus et peditibus exercitus Pii Fidelis qui militant in alis VI(?) et cohortibus XXV(?) quae appellantur Sulpic(ia) et Indian(a) et I Noricor(um) et I Batavor(um) et 3 et Afror(um) et I Hispanor(um) et I Pannonior(um) et 3 et I Thrac(um) et I Flavia Hispanor(um) et I Pannonior(um) et Delmatar(um) c(ivium) R(omanorum) et I Vindelicor(um) c(ivium) R(omanorum) mil(liaria) et I Raetor(um) c(ivium) R(omanorum) et I classica et I Lucensium et I] La[tob]icor(um) et Varcian[or(um) et I et II c(ivium) R(omanorum) et II et II Hispano]r(um) et II Astur(um) II Varcian(orum) et II [Brittonum mil(liaria) et II Thr]ac(um) et III Lusitanor(um) et III Breucor(um) [e]t I[III Thrac(um) et VI ] Breucor(um) et VI Raetor(um) et VI Brittonum [et sunt in Germani]a inferiore sub Imp(eratore) Traiano Aug(usto) [qui quina et v]icena plurave stipendia meruerun[t item dimissis ho]nesta missione emeritis stipendiis e[t classicis qui milit]ant sub eodem praef(ecto) L(ucio) Calpurnio Sab[ino senis et vic]enis stipendiis emeritis quorum no[mina subscrip]ta sunt ipsis liberis posterisque e[orum civitatem d]edit et conubium cum uxoribu[s quas tunc habuiss]ent cum est civitas iis data aut s[iqui caelibes essent cu]m iis quas postea duxissent du[mtaxat singuli sing]ulas a(nte) d(iem) X K(alendas) Mart(ias) Imp(eratore) C[aes(are) Traiano Aug(usto) G]er(manico) II Sex(to) Iulio Frontino II co[(n)s(ulibus) alae I Ba]tavorum cui prae(e)st [3] T(iti) f(ilius) Vol(tinia) Rufus [dimis]so honesta missione / ex gregale [3] Gaveri f(ilius) Batav(o) [et 3 Pere]grini filiae uxori eius Bat(avae) [et 3 a]e fil(ius) eiu[s et 3]ae fil(ius) [eius descriptum et] recognitum ex t[abula aenea quae fixa est Ro]mae in mur[o post templum divi Aug(usti) ad Minerva]m // [Imp(erator) Caesar divi Nervae f(ilius) Nerva Traianus Aug(ustus) Germ(anicus) pont(ifex) maxim(us) trib(unicia) potest(ate) co(n)s(ul) II equitibus et peditibus exercitus Pii Fidelis qui militant in alis VI(?) et cohortibus XXV(?) quae appellantur Sulpic(ia) et In]dian(a) et I Noricor(um) / [et I Batavor(um) et 3 et Af]ror(um) et I Hispanor(um) et I Pannonior(um) / [et 3 et I Thrac(um) et I Fl]avia Hispanor(um) et I Pannonior(um) et Delmatar(um) / [c(ivium) R(omanorum) et I Vindel]icor(um) c(ivium) R(omanorum) mil(liaria) et I Raetor(um) c(ivium) R(omanorum) et I classica et I Lu/[censium et I Lat]obicor(um) et Varcianor(um) et I et II c(ivium) R(omanorum) et II et II Hispa/[nor(um) et II Ast]ur(um) et II Varcianor(um) et II Brittonum mi/[l(liaria) et II Thrac(um) et III L]usitanor(um) et III Breucor(um) et IIII Thrac(um) / [et VI Breucor(um) et VI Rae]tor(um) et VI Brittonum et sunt in Germ(ania) / [inferiore su]b Imp(eratore) Tra(i)ano Aug(usto) qui quin[a et vicena plurave stipe]ndia mer[uerunt i]tem dimiss[is honesta missione emeritis stipendis et] classicis q[ui militant sub eodem praef(ecto) L(ucio) Calpurnio Sabi]no senis et

[D B Campbell]

What we need is a Batavus serving in Lower Germany after Vespasian's supposed ban on Germans serving near their homeland.

Here you go Duncan. Gaverius a cavalryman.. (RMD-04, 00216 )

Thanks for posting that, Adrian. I must confess that I was being rather mischievous. Paul Holder had earlier drawn my attention to this very diploma. A Batavus discharged in AD 98 in Germania Inferior raises very interesting possibilities, as he would've enlisted in AD 73, in the aftermath of the Batavian Revolt. This implies that the ala Batavorum of Tac., Hist. IV.18 was still in Germ. Inf. in that year, contrary to our assumption regarding Vespasian's "new policy". (Unfortunately its precise whereabouts between enlisting our Batavus in Germ. Inf. in AD 73 and gaining the honorific titles pia fidelis in Germ. Inf. in AD 89 are not known.)

P.S. Note that your man's father was Gaver(i)us; his own name has not survived.

[Peroni]

P.S. Note that your man's father was Gaver(i)us; his own name has not survived.

So it does! :oops:

[Rumo]

Unfortunately its precise whereabouts between enlisting our Batavus in Germ. Inf. in AD 73 and gaining the honorific titles pia fidelis in Germ. Inf. in AD 89 are not known

We have pf only in this diploma from AD 98 (and later). Paul Holder (in "Exercitus Pius Fidelis: The Army of Germania Inferior in AD 89" published in the same ZPE, 128/1999, pag. 237–250) assumed Domitian granted this honor to all units in Germania Inferior in AD 89 when he supressed the rebellion of Saturninus. Yet, AFAIK, there's no solid evidence this was the case. Let's take a look at the alae pf from AD 98 and the reconstruction Holder suggested in 1999:

AD 89 (Holder): III Asturum cR, I Batavorum, II Flavia milliaria, Indiana Gallorum, Moesica felix, I singularium cR, II Thracum Augusta
AD 98 (RMD IV 216): Suplicia, Indiana, I Noricorum, I Batavorum, ... , Afrorum; here's a hasty identification with what I know from other inscriptions: Suplicia cR, Indiana Gallorum, I Noricorum cR, I Batavorum, Afrorum veterana and that unknown ala.

What I see is that from the five alae pf attested in AD 98 in Germania Inferior only two are to be found in Holder's reconstruction for AD 89. Sure, his line of argumentation may be improved, my point is that for the moment an ala I Batavorum pia fidelis in AD 89 in Germania Inferior is only a conjecture.

[D B Campbell]

my point is that for the moment an ala I Batavorum pia fidelis in AD 89 in Germania Inferior is only a conjecture.

Granted. I'm well aware of the evidence, but thank you for setting it out. So, technically, the whereabouts of ala Batavorum are unknown from AD 73 (Germ. Inf.) to AD 98 (Germ. Inf.), and it could well have been in a different province at some point in the meantime.

For our purposes, the interesting fact is that the ala Batavorum was in its home province in AD 73, at a time when, according to the theory of Vespasian's "new policy", it shouldn't have been.

[Rumo]

I have to admit your argument seems compelling. My concession is partial because I still have some doubts about the patterns of recruitment and discharge in and from auxilia.

For your argument to work the location of discharge must coincide more or less with the one of recruitment, and also the recruitment must be largely local (in a unit stationed in that region) and definitive (so that a Batavus wasn't first recruited in another unit and only later transferred to this ala).

[D B Campbell]

For your argument to work the location of discharge must coincide more or less with the one of recruitment, and also the recruitment must be largely local (in a unit stationed in that region) and definitive (so that a Batavus wasn't first recruited in another unit and only later transferred to this ala).

OK -- our fixed points are these: we know that the ala Batavorum was in Germ. Inf. in AD 70 (Tac., Hist. IV.18); we know that the ala Batavorum discharged men in Germ. Inf. in AD 98. I concede that we don't know where it was in the meantime, although its honorific title, pia fidelis, suggests a link with Germ. Inf. in AD 89.

I am assuming that local recruitment was the norm. So a Batavus would be recruited into a local unit. Our man, recruited in AD 73, ended up in the ala Batavorum. This suggests that the ala was his local unit in Germ. Inf.

I concede that absolute certainty is impossible. In a "worst-case scenario", the ala Batavorum may have moved away from Germ. Inf. shortly after AD 70, and our man may have been sent to join it, when he enlisted in AD 73. I prefer the "best-case scenario" !

(Incidentally, the fact that the ala Batavorum was back in Germ Inf. in AD 89/98 shows that Vespasian's policy, if he had one, didn't last long.)

[Rumo]

Perhaps you already know of this Roman fort discovered in Nijmegen. Jona suggests it is likely this fort was the home of ala I Batavorum before AD 70. If so, our ala was relocated after the revolt, as this fort was never used again.
Of course, that doesn't mean the unit was moved away from this province, only that its history between AD 69 and AD 98 might be a bit more "dynamic" than what an attractive interpolation would make us believe.

On recruitment and further transfers I think it's safe to assume (until proven otherwise) that regardless what the general tendency was, the patterns had also components which were variable in time and space. Last year I mentioned an ostrakon revealing that in 109 all Dacian auxiliary soldiers serving in Egypt (enrolled in "non-Dacian" units such as one ala Vocontiorum) were summoned in Alexandria. We can only speculate why. One plausible reason is the creation of a Dacian auxiliary unit. Not in Dacia, but in Egypt, many miles away.

But don't get me wrong, I am just exploring scenarios here. Your argument has its merit, and indeed it may be the case that ala I Batavorum was stationed somewhere in Germania Inferior in early 70s. So one is entitled to doubt a policy of Vespasian sending Batavian units far away from lower Rhine.

[Gaius Julius Caesar]

It would seem feasible that a unit could not serve in a location, i.e. the homeland it was raised in,
but the actual recruits were raised there, sent out in batches, and on retirement, return home?
No Imperial Edicts broken?