Letters Home from the Roman Forces in Britain
The Vindolanda tablets (also known as Vindolanda Letters) are thin pieces of wood about the size of a modern postcard, which were used as writing paper for the Roman soldiers garrisoned at the fort of Vindolanda between AD 85 and 130.
These kinds of tablets are referred to as leaf tablets or sectiles or laminae—Pliny used them to keep notes for his Natural History, written in the first century AD.
The correspondent wrote in ink before folding the leaf in half and writing the address on the back. In some cases, longer documents have been created by punching holes in the corner and tying several of these tablets together.
Documents such as these were not uncommon in the Roman world, and were even described by Herodian, who talks of the emperor Commodus making a list of proscribed persons by: ‘taking a writing-tablet of the kind that were made of lime wood and folded face-to-face by being bent.’ It was the discovery of this list which prompted his assassination.
The Vindolanda tablets are made of birch, alder and oak. Chance finds from other sites in Britain indicate that they were not unique, and the vast volume of them in the anaerobic conditions of Vindolanda suggest that such tablets were ubiquitous in the northern provinces as means of record-keeping and letter-writing where papyrus was scarce.
They can tell us a great deal about the nature of life on the Roman frontier, not just in a military context. The vast majority of them date from the period AD 97-103, when the fort was occupied by IX Batavorum and its sister unit III Batavorum,both ‘quingenary‘ units approximately 500 strong, as well as a detachment of cavalry from the Spanish Ala Vardullorum.
It is almost impossible to separate the military activities of Vindolanda from its civilian activities, as you will see, since the two naturally blend into one. Yet the Vindolanda tablets can tell us some very interesting things about the way the Roman army was run on the northern frontier.
They show is just what a well-oiled machine the Roman army was. Much of the Vindolanda material is made up of accounts, work rosters, and interim reports. Its value lies in its very nature as interim material, used to write up the more formulaic official reports which we find elsewhere, such as at Dura and in Egypt.
These not only demonstrate how such a small number of men could be used to police and control such a wide frontier, but the extent to which the army was always engaged in non-military activities that interacted with the local area.
The writers wrote exclusively in Latin , although the texts mostly lack punctuation or proper spelling; there is even some Latin shorthand which has yet to be deciphered.
Some of the texts are rough drafts of letters that were later sent; the writers include soldiers, officers and their wives and families who were garrisoned at Vindolanda, as well as merchants and slaves and correspondents at many different cities and forts throughout the vast Roman empire, including Rome, Antioch, Athens, Carlisle, and London. Some of the tablet seven have doodles and drawings on them.
The tablets were written on with pen and ink–over 200 pens have been recovered at Vindolanda.
The most common pen nib was made of a good quality iron by a blacksmith, who sometimes embellished them with chevrons or bronze leaf or inlay, depending on the customer. The nib was typically attached to a wood holder that held a well of ink made of a mixture of carbon and gum arabic.
In Latin texts, such as those of Pliny the Elder, . The surface of the wood was smoothed and treated so it could be used for writing. Often the tablets were scored in the center so that they could be folded and tied together for security purposes–to keep couriers from reading the contents. Longer documents were created by tying several leaves together.
Vindolanda is one of the most fascinating snapshots of Roman life and has been preserved for posterity. As such, it transcends the basic military significance of the find and, like so much else of the Roman army (around which the Roman system revolved), sheds light upon the everyday lives of those who lived and worked in and around the camp. The Vindolanda tablets provide a unique insight into what it must have been like to be a Roman representative in a foreign land.
The Britons are unprotected by armour. There are very many cavalry. The cavalry do not use swords, nor do the wretched Britons [Brittunculi] mount in order to throw javelins.(Tab. Vindol. II.164)
The memorandum above was probably written by one of the commanders at Vindolanda as informative notes to his successor. It graphically portrays the frustrations of the regular soldier when faced with a guerrilla army that will not stand and fight, rather like the experience of American soldiers in Vietnam.
Frontier zone
The Roman army at this time was in a period of retrenchment. In AD 84, Agricola had defeated the Caledonii of south-eastern Scotland at Mons Graupius, and was (according to his somewhat partisan biographer Tacitus) poised to conquer the rest of Britain when his army was recalled by the emperor Domitian, who needed it for his Chattan wars on the Rhine.
Large detachments of troops were withdrawn from the province, and those that were left established a frontier zone called a limes [pronounced leem-ays] along the military road of the Stanegate which ran from Carlisle to Corbridge (approx.).
Hadrian’s Wall… a permeable frontier, designed to control the movements of the tribes within the border zone and to regulate commerce between Roman Britain and its barbarian neighbours.
The fact that the limes was not fixed at the narrower neck of land between Edinburgh and Glasgow suggests strongly that the Scottish tribes had not been quite as comprehensively trounced as Tacitus would like us to believe, as do tombstones and snippets of official correspondence which hint at troubles in the north during this time.
However, it would be a mistake to view the limes as a static defensive line. Even when Hadrian’s Wall was erected some thirty years later, it was never that. It was a permeable frontier, designed to control the movements of the tribes within the border zone and to regulate commerce between Roman Britain and its Barbarian neighbors.
As such, the troops within it fulfilled a similar sort of police function as those British troops who used to guard Hong Kong. Pivotal to this system was the fort of Vindolanda, which sat at the approximate centre of the frontier.
Like most Roman forts, Vindolanda followed several phases of construction. Originally a turf rampart, probably erected in the time of Agricola, by the late 80s AD it was a permanent turf and timber fort in the classic Roman playing-card shape, aligned east-west, with a stone headquarters building, an officer’s house, and a small bathhouse situated down the slope on the eastern side. During the Hadrianic period (c.120 and after), this whole fort was demolished and a new structure was built facing north-south.
Attached to the west of this Hadrianic fort was a small civilian settlement, called a vicus, within the remains of the old rampart and which incorporated a fine bathhouse and a mansio, a guesthouse with space for up to six residents travelling along the Stanegate on official business.
All of this was enlarged and rebuilt in stone during the early third century AD, and it is this ground plan that we see today. The famous Vindolanda tablets date to the pre-Hadrianic fort, though they are typical of Roman military life in any period.
The soldiers
…Rome followed a policy of not allowing native troops to serve within their province of origin.
Vindolanda was garrisoned at different times by several units, most importantly the First Cohort of Tungrians and the Third and Ninth Cohorts of Batavians. These were auxiliary units, made up of non-citizen recruits who served for a period of up to 25 years in return for Roman citizenship.
None were Britons. This is because of a policy prompted by the revolt of these very units in AD 69. In the wake of the infamous Year of the Four Emperors, the Dutch Batavian auxiliaries had mutinied against the emperor Vespasian, joined by their neighbours the Tungrians on the River Meuse.
It had taken five Roman legions to subdue them, commanded by the veteran general Q. Petilius Cerialis. He had taken the subdued auxiliaries with him on his next tour of duty, to Britain, where they stayed. From then on, Rome followed a policy of not allowing native troops to serve within their province of origin.
The units were commanded by their own tribal chieftains, but were gradually diluted by recruits from other areas. The names on the Vindolanda tablets suggest origins from Gaul, Germany, Pannonia, Dacia and Greece (probably Greek slaves) as well as the upper Rhine homelands of the original units.
Military life
The most fascinating military document to come out of the material is a strength report of the double-strength military cohort I Tungrorum, which shows just how many men could be absent from home base at any one time. (Tab. Vindol. I.154):
’18 May, net number of the First Cohort of Tungrians, of which the commander if Iulius Verecundus the prefect, 752, including 6b centurions.’
This lends weight to what we have long thought, that Roman frontier units were not static entities stuck in one place, but had men all over the place.
It is significant that the vast majority of the troops were not even stationed in their own home base, but were elsewhere. Corbridge was the big granary fort at the eastern end of the Stanegate (and this is the only evidence we have of I Tungrorum occupying it, at almost quingenary strength).
It is interesting to see how far afield some of the troops were, for whatever reason. God alone knows what the men in Gaul were doing there (though bear in mind that I Tungrorum was technically a Gallo-Belgic unit); but the six men with a centurion were probably garrisoning an outpost or on patrol.
There are at least a dozen formulaic leave requests written by soldiers in the fort to lend weight to this: ‘I, [so-and-so], ask that you consider me a worthy person to grant leave at [such-a-place]’.
Roman writing equipment from Verulamium (St Albans). Only the lamp, wax tablet & wafer thin wood tablets are modern replicas. The ink pot, stylus, seal box and signet ring are original finds.
The centurion in London was probably carrying official correspondence to the governor’s office. Once again, we have evidence of centurions acting as couriers like this.
A letter from the cavalry decurion Masculus to Flavius Cerialis, Verecundus’ successor in the fort, illustrates just how involved the commander could be in determining these assignments:
Masculus to Cerialis his king, greetings. Please, my lord, give instructions on what you want us to do tomorrow. Are we all to return with the standard, or just half of us?…(missing lines)…most fortunate and be well-disposed towards me. My fellow soldiers have no beer. Please order some to be sent.
Another report of work assignments shows how these men could be employed. Of 343 men present, 12 were making shoes, 18 were building the bath-house, others were out collecting lead, clay and rubble (for the bath-house?), while still more were assigned to the wagons, the kilns, the hospital and on plastering duty. Other accounts indicate that the completed bath-house had a balniator, a bath-house keeper called Vitalis. The remains of the third-century bath-house on the site give a very good idea of what Vitalis’ bath-house must have been like.
…two vets called Virilis and Alio, a shield-maker called Lucius, a medic called Marcus and a brewer called Atrectus.
Other trades attached to the fort were two vets called Virilis and Alio, a shield-maker called Lucius, a medic called Marcus and a brewer called Atrectus. Most of these must have been soldiers, but, civilians also played their part within fort life.
Atrectus the brewer owed money to the local pork butcher for iron and pork-fat, which smacks of a little economic diversification on the butcher’s part. It is not at all clear whether the butcher was a civilian or a soldier.
He is likely to have been a civilian. This an intriguing account of wheat which paints a marvellous picture of everyday life at the fort. It is a long account,excerpted only the clearest entries. [NB: a modius is a measure of weight] (Tab. Vindol. II.180):
The document is clearly the account of a family business run by two brothers, whose father occasionally tends the oxen.
Wide boys
Along and very well preserved letter, from Octavius to his brother Candidus, gives us the names of these two brothers and portrays them as a couple of local wide-boys, with their fingers in as many pies as possible (Tab. Vindol. II 343)
So, I ask you, send me some cash as soon as possible.
Octavius to his brother Candidus, greetings. The hundred pounds of sinew from Marinus,
I will settle up. From the time when you wrote about this matter, he has not even mentioned it to me. I have several times written to you that I have bought about 5,000 modii of ears of grain, on account of which I need cash.
Unless you send me some cash, at least 500 denarii, the result will be that I shall lose what I have laid out as a deposit, about 300 denarii, and I shall be embarrassed.
So, I ask you, send me some cash as soon as possible. The hides which you write are at Cataractonium, write that they be given to me and the wagon about which you write. And write to me what is with that wagon. I would have already have been to collect them except that I did not care to injure the animals while the roads are bad.
See with Tertius about the 8½ denarii which he received from Fatalis. He has not credited them to my account. Know that I have completed the 170 hides and I have 119(?) modii of threshed bracis.
Make sure that you send me some cash so that I may have ears of grain on the threshing room floor. Moreover, I have already finished threshing all that I had.
A messmate of our friend Frontius has been here. He was wanting me to allocate(?) him some hides, and that being so, was ready to give cash. I told him I would give him the hides by the Kalends of March.
He decided that he would come on the Ides of January. He did not turn up, nor did he take the trouble to obtain them since he had hides. If he had given the cash, I would have given him them. I hear that Frontinius Julius has for sale at a high price the leather ware(?) which he bought here for five denarii apiece. Greet Spectatus and …and Firmus. I have received letters from Gleuco. Farewell.
Entrepreneurs
Candidus was obviously so well known in the fort that his brother did not need to put his name on the back for whoever was delivering the note. The two seem to have the supply of grain to Vindolanda sewn up (which is interesting when you consider that the military granary of Corbridge was just down the road).
The regular allocations to Macrinus and Crescens are probably rations doled out to individual unit centurions: since a Crescens is named as a centurion of III Batavorum.
In that case, who are Firmus and Spectatus? Clearly Firmus is a key individual, as he has the authority to allocate grain to a detachment of legionaries in the fort; yet does this mean that he is a senior centurion of one of the cohorts, or is he just a middle-man? Since Spectatus uses grain as a loan to Victor, it seems most likely that they were agents of the brothers (though this does not necessarily stop them being soldiers).
…the annual pay of an auxiliary soldier at this time was about 300 denarii…
The two brothers were civilian entrepreneurs, and when you consider that the annual pay of an auxiliary soldier at this time was about 300 denarii, they were obviously not in the little-league if they could fork out 500 denarii for their grain supplies.
The fact that they had Roman names can tell us little, since anyone who wanted to get on is likely to have ‘Romanised’ by this time.
One possibility does come to mind. Given the Roman penchant for farming out public services (like tax-collecting and mining) to individual entrepreneurs, it is possible that these two men had the contract for supplying grain to the army from Corbridge.
Flavius Cerialis and his family
The Vindolanda tablets give insights into the personal lives of somepeople who inhabited the fort. Naturally, this is most graphic for the officers of the fort, especially since the majority of the tablets were found in a rubbish tip linked to the commander’s house, but there are things they can say about the lesser individuals who lived and worked in the vicinity also.
Flavius Cerialis was the praefectus in command of Cohors IX Batavorum, which occupied Vindolanda from around AD 97 onwards.
His name indicates that his family was granted the citizenship by the Flavian dynasty of Vespasian, and the cognomen Cerialis may have been in honour of Q. Petilius Cerialis, who brought the Batavians over to Britain.
He was a Batavian nobleman of equestrian status, which meant that his family had amassed a fortune of over 400,000 sesterces (100,000 denarii), the property qualification for entry into the equestrian order.
Patronage
Request letters of recommendation for their friends. One of these survives, from a certain Claudius Karus. (Tab. Vindol. II.250):
Brigionus has requested me, my lord, to recommend him to you. I therefore ask, my lord, if you would be willing to support him. I ask that you think fit to commend him to Annius Equester, the centurion in charge of the region at Luguvalium, by doing which you will place me in debt to you, both in his name and my own.
Brigionus is a Romanised Celtic name, this as a classic example of patronage, by which the subjects of the frontier region were absorbed into the Roman system.
Karus, a fellow officer, recommends to Cerialis a British client, and requests that he pass him on in turn to the regional administration officer for the legions, Annius Equester, whether as a potential recruit or for some other purpose is not clear (though given that it is being done through military channels, I would suspect the former).
Promotion
Cerialis clearly had good contacts of his own, with which he was trying to negotiate a promotion. Here are a couple of letters edited them for intelligibility:
[Cerialis ] to his Crispinus… Since Grattius Crispinus is returning to [you], I have gladly seized this opportunity, my lord, of greeting you, whom I dearly wish to be in good health and master of all your hopes. For you have always deserved this of me, right up to your present high office… greet Marcellus, that most distinguished man, my governor. He offers opportunity for the talents of your friends, now that he is here, for which I know you thank him. Now, in whatever way you wish, fulfil what I expect of you and… so furnish me with very many friends, so that thanks to you I may be able to enjoy an agreeable period of military service. I write this to you from Vindolanda, where my winter quarters are. (Tab. Vindol. II.225)
Niger & Brocchus to their Cerialis, greeting. We pray, brother, that what you are about to do is most successful. It will be so indeed, since our prayers are with you and you yourself are most worthy. You will assuredly meet our governor quite soon. (Tab. Vindol.II.248)
…he was clearly a high-ranking official in the province, with the ear of the provincial governor…
Who Crispinus is not known , but he was clearly a high-ranking official in the province, with the ear of the provincial governor, L. Neratius Marcellus (Leg. Brit. AD 100-103). Cerialis obviously hoped by his patronage to gain a promotion from the governor, and his friends and fellow officers, Niger & Brocchus, clearly wished him well.
The somewhat tart: ‘I write this to you from winter quarters in Vindolanda.’ might give some indication of how Cerialis viewed life up on the cold north-west frontier, as does another letter to a fellow officer, an aptly named September, offering to send him some goods: ‘by which we may endure the storms, even if they are troublesome.’
Family and Leisure time
on the north-west frontier was clearly less than exciting for the officer classes.
Cerialis writes to Brocchus in another letter asking for some hunting nets: ‘and please make sure that they are repaired strongly’. Brocchus was the commander of a nearby fort called Briga(Celtic for ‘hill’), which we cannot identify. His wife, Claudia Severa, was in regular correspondence with Cerialis‘ wife, Sulpicia Lepidina. The most famous of these is the well-known birthday invitation. (Tab. Vindol. II.291):
…for the day of the celebration of my birthday, I give you a warm invitation…
Claudia Severa to her Lepidina greetings. On the third day before the Ides of September, sister, for the day of the celebration of my birthday, I give you a warm invitation to make sure that you come to us, to make the day more enjoyable for me by your arrival, if you are present(?). Give my greetings to your Cerialis. My Aelius and my little son send him(?) their greetings. I shall expect you sister. Farewell, sister, my dearest soul, as I hope to prosper, and hail.
In fact, the officer classes seem to have been engaged in a constant round of visits. Another letter from Claudia Severa informs Lepidina that Brocchus will always let her come to Vindolanda to visit whenever she can, while several accounts by the household slaves indicate that Brocchus had donated tunics to the Cerialis household in the past, and in return had dined on several occasions, both with and without his friend Niger, on which occasions chickens were slaughtered. Finally, a cryptic line at the end of one list of accounts informs us that on 25 June: ‘The lords have remained at Briga‘.
We do not know whether Cerialis was successful in pursuing his promotion, but we do know about his friend. C. Aelius Brocchus went on to command the prestigious Ala Contariorum in Pannonia.
At times, official channels could be abused, or at least stretched, in order to accommodate those in the position to take advantage of them. A legionary centurion called Clodius Super asks Cerialis to send him some clothing Cerialis had picked up from a friend in Gaul, saying: ‘I am the supply officer, so I have acquired transport’. (Tab. Vindol. II.255).
Family visits
On a more personal note, a certain Velde(d)ius, who had secured a promotion to act as groom of the governor down in London, visited his ‘brother and old messmate’ Chrauttius en route to Housesteads. He probably stayed in the mansio, since he was on official business of some sort, and may have dropped off the shears which Chrauttius had asked him to get for him in the letter, which he discarded whilst he was there. He also left behind a leather offcut with his name inscribed upon it, and may have owned the magnificent chamfron which was found nearby.
The two of them probably exchanged news about their ‘sister’, Thuttena, and various old messmates whom Chrauttius had mentioned in his letter. Veldedius then went on to Housesteads, where he died in unknown circumstances and an official tombstone was erected, with his name slightly mis-spelled, though it is still likely to have been the same man. (Tab. Vindol. II.310).
Mensa
he diet of the inhabitants of Vindolanda was pretty varied. Within the tablets, 46 different types of foodstuff are mentioned. Whilst the more exotic of these, such as roe deer, venison, spices, olives, wine and honey, appear in the letters and accounts of the slaves attached to the commander’s house; it is clear that the soldiers and ordinary people around the fort did not eat badly.
We have already seen the grain accounts of the brothers Octavius and Candidus, demonstrating that a wide variety of people in and around the fort were supplied with wheat. Added to that are a couple of interesting accounts and letters which show that the ordinary soldiers could get hold of such luxuries as pepper and oysters, and that the local butcher was doing a roaring trade in bacon.
Clothing
One list in particular is interesting, because it seems to illustrate the standard military practice of docking pay in return for some form of centralised supply. The tablet contains a list of men arranged by century, from the centuries of Ucenius and Tullioson of Carpentarius, who have been provided with various goods such as overcoats, towels, a flask, a cloak, thongs, tallow and in the case of Gambax son of Tappo, pepper.
There are check marks to the left of several of these entries, as if they have been ticked off once they have paid, and we are able to ascertain from the fuller entries what the cost of certain commodities were. For instance, a towel cost 2 denarii, Gambax had 2 d worth of pepper, and Lucius the shieldmaker paid 5 d 3 asses for a cloak (Tab. Vindol. II.184).
I have sent(?) you…pairs of socks from Sattua, two pairs of sandals and two pairs of underpants…
Instead of paying for such items, the more fortunate soldiers in the unit could expect parcels from their families containing the basics of life, as in the case of this anonymous soldier (Tab. Vindol. II.346):
I have sent(?) you…pairs of socks from Sattua, two pairs of sandals and two pairs of underpants, two pairs of sandals…Greet…Elpis…Tetricus and all your messmates with whom I pray that you live in the greatest good fortune.
Imstructions on a certain letter of practice.
If he had lice, there were baths, soap and towels; for the cold, a medical service and a hospital; if looking at the sky gave him inflamed eyes, he could sign on the sick list. If he was lonely, he could take leave and find a friend in Corbridge, or perhaps even go home to Tungria. But it would be optimistic to suppose that even the Roman army could stop the rain pattering out of the sky in a climate notorious for its tempestates molestae.’
About the author
Dr Mike Ibeji is a Roman military historian who was an associate producer on Simon Schama’s A History of Britain.
What did the Romans Write?
Topics covered on the tablets include letters to friends and families (“a friend sent me 50 oysters from Cordonovi, I’m sending you half” and “So that you may know that I am in good health… you most irreligious fellow who hasn’t even sent me a single letter”); applications for leave (“I ask you, Lord Cerialis, that you hold me worthy for you to grant me leave”); official correspondence; “strength reports” listing the number of men present, absent or ill; inventories; supply orders; travel expense account details (“2 wagon axles, 3.5 denarii; wine-lees, 0.25 denarii”); and recipes.
One plaintive plea to the Roman emperor Hadrian himself reads: “As befits an honest man I implore Your Majesty not to allow me, an innocent man, to have been beaten with rods…” Chances are this was never sent. Added to this are quotations from famous pieces: a quote from Virgil’s Aeneid is written in what some, but not all scholars interpret as a child’s hand.
Finding the Tablets
The recovery of over 1300 tablets at Vindolanda (to date; tablets are still being found in the ongoing excavations run by the Vindolanda Trust) is the result of serendipity: a combination of the way the fort was constructed and the geographic location of the fort.
Vindolanda was built at the place where two streams conjoin to create the Chinley Burn, which ends up in the South Tyne river. As such, the fort’s occupants struggled with wet conditions for most of the four centuries or so that the Romans lived here. Because of that, the floors of the fort were carpeted with a thickish (5-30 cm) combination of mosses, bracken, and straw. Into this thick, smelly carpet were lost a number of items, including discarded shoes, textile fragments, animal bone, metal fragments and pieces of leather: and a large number of Vindolanda tablets.
In addition, many tablets were discovered in filled-in ditches and preserved by the wet, mucky, anaerobic conditions of the environment.
Reading the Tablets
The ink on many of the tablets is not visible, or not readily visible with the naked eye. Infrared photography has been used successfully to capture images of the written word.
More interestingly, the fragments of information from the tablets have been combined with other data known about Roman garrisons. For example, Tablet 183 lists an order for iron ore and objects including their prices, which Bray (2010) has used to learn about what the cost of iron was relative to other commodities, and from that identify the difficulty and utility of iron out on the edges of the far-flung Roman empire.
Sources
Images, texts, and translations of some of the Vindolanda Tablets can be found at the Vindolanda Tablets Online. Many of the tablets themselves are at stored at the British Museum and visiting the Vindolanda Trust website is well worth it as well.
Birley A. 2002. Garrison Life at Vindolanda: A Band of Brothers. Stroud, Gloucestershire, UK: Tempus Publishing. 192 p.
Birley AR. 2010. The nature and significance of extramural settlement at Vindolanda and other selected sites on the Northern Frontier of Roman Britain. Unpublished PhD Thesis, School of archaeology and Ancient History, University of Leicester. 412 p.
Birley R. 1977. Vindolanda: A Roman frontier post on Hadrian’s Wall. London: Thames and Hudson, Ltd. 184 p.
Bowman AK. 2003 (1994).
Life and Letters on the Roman Fronteir: Vindolanda and its People. London: British Museum Press. 179 p.
Bowman AK, Thomas JD, and Tomlin RSO. 2010. The Vindolanda Writing-Tablets (Tabulae Vindolandenses IV, Part 1). Britannia 41:187-224. doi: 10.1017/S0068113X10000176
Bray L. 2010. “Horrible, Speculative, Nasty, Dangerous”: Assessing the Value of Roman Iron. Britannia 41:175-185. doi:10.1017/S0068113X10000061
Carillo E, Rodriguez-Echavarria K, and Arnold D. 2007. Displaying Intangible Heritage Using ICT. Roman Everyday Life on the Frontier: Vindolanda. In: Arnold D, Niccolucci F, and Chalmers A, editors. 8th International Symposium on Virtual Reality, Archaeology and Cultural Heritage VAST