Castra The Latin word castra , with its singular castrum , was used by the ancient Romans to mean buildings or plots of land reserved to or constructed for use as a military defensive position . The word appears in both Oscan and Umbrian ( dialects of Italic ) as well as in Latin . In classical Latin the word " castra " always means " great legionary encampment " , both " marching " , " temporary " ones and the " fortified permanent " ones , while the diminutive form castellum was used for the smaller forts , which were usually , but not always , occupied by the auxiliary units and used as logistic bases for the legions , as explained by Vegetius . A generic term is praesidium ( " guard post or garrison " ) . The terms stratopedon ( " army camp " ) and phrourion ( " fort " ) were used by Greek language authors , in order to designate the Roman " castra " and the Roman " castellum " respectively . In English , the terms " Roman fortress " , " Roman fort " and " Roman camp " are commonly used for the " castra " . However the scholars ' convention always requires the use of the word " camp " , " marching camp " and " fortress " as a translation of " castra " and the use of the word " fort " as a translation of " castellum " and this type of convention is usually followed and found in all the scholarly works . Etymology . According to Julius Pokorny , " Indogermanisches Etymologisches Woerterbuch " , page 586 under " kes - " ( palatal " k " ) , Oscan " castrous " ( genitive case ) and Umbrian " castruo " , " kastruvuf " ( nominative case ) have the same original meaning as castrum , which was an estate , or a tract of land . Being the term used to designate a private estate , in Latin the word " castrum " was probably then the term for an estate or a tract of land enclosed by a fence or a wooden or stone wall of some kind , as seems to be used in a few passages in Cornelius Nepos ' works . The " American Heritage Dictionary " , following Julius Pokorny , lists * kes - , " cut " , as the root . One castrum was a reservation of land " cut off " for military use . It could be an entire base , such as " castrum Moguntiacum " , or it could be a single fortified building . From the latter use came the English word castle ( castellum , a diminutive of castrum ) . In Latin the term " castrum " is much more frequently used as a proper name for geographical locations : e . g . Castrum Album , Castrum Inui , Castrum Novum , Castrum Truentinum , Castrum Vergium . " Castra " in the plural refers to a collection of structures . Considering that the earliest structures were tent s , which were cut out of hide or cloth , one castrum may well be a tent , with the plural meaning tents . All but the most permanent bases housed the men in barracks of tents placed in quadrangles and separated by numbered streets . The term " castra " then means " marching camp " , " temporary camp " , " permanent camp " , " fortified camp " and " fortress " , always designating a great legionary encampment . The plural was also used as a place name , as Castra Cornelia , and from this plural come the English place name suffixes such as - caster and - chester ; e . g . Winchester , Lancaster . The commonest Latin syntagmata for the term " castra " are : " Castrorum Filius " was one of names used by the emperor Caligula and then also by other emperors . " Castro " , also derived from " Castrum " , is a common Spanish family name , as well as a place name in Spain and Spanish - speaking countries , Italy and the Balkan , either by itself or in various compounds such as Argyrocastro ( see Castro ) . Types of castra . The best known type of castra is the camp , a military town designed to house and protect the soldiers and their equipment and supplies when they were not fighting or marching . Regulations required a major unit in the field to retire to a properly constructed camp every day . " . . . as soon as they have marched into an enemy ' s land , they do not begin to fight till they have walled their camp about ; nor is the fence they raise rashly made , or uneven ; nor do they all abide ill it , nor do those that are in it take their places at random ; but if it happens that the ground is uneven , it is first leveled : their camp is also four - square by measure , and carpenters are ready , in great numbers , with their tools , to erect their buildings for them . " To this end a marching column ported the equipment needed to build and stock the camp in a baggage train of wagons and on the backs of the soldiers . Camps were the responsibility of engineering units to which specialists of many types belonged , officered by " architecti " , " chief engineers " , who requisitioned manual labor from the soldiers at large as required . They could throw up a camp under enemy attack in as little as a few hours . Judging from the names , they probably used a repertory of camp plans , selecting the one appropriate to the length of time a legion would spend in it : " tertia castra " , " quarta castra " , etc . , " a camp of three days " , " four days " , etc . More permanent camps were " castra stativa " , " standing camps " . The least permanent of these were " castra aestiva " or " aestivalia " , " summer camps " , in which the soldiers were housed " sub pellibus " or " sub tentoriis " , " under tents " . Summer was the campaign season . For the winter the soldiers retired to " castra hiberna " containing barracks and other buildings of more solid materials , with timber construction gradually being replaced by stone . The camp allowed the Romans to keep a rested and supplied army in the field . Neither the Celtic nor Germanic armies had this capability : they found it necessary to disperse after only a few days . Plan of the fort . Sources and origins . Even from the most ancient times Roman camps were constructed according to a certain ideal pattern , formally described in two main sources , the " De Metatione Castrorum " or " De Munitionibus Castrorum " by either Hyginus Gromaticus or Pseudo - Hyginus and the works of Polybius . Vegetius has a small section on entrenched camps as well . The terminology varies some but the basic plan is the same . The hypothesis of an Etruscan origin is a viable alternative . Layout . The ideal enforced a linear plan for a camp or fort : a square for camps to contain one legion or smaller unit , a rectangle for two legions , each legion being placed back - to - back with headquarters next to each other . Laying it out was a geometric exercise conducted by experienced officers called " metatores " , who used graduated measuring rods called " decempedae " ( " 10 - footers " ) and " gromatici " who used a groma , a sighting device consisting of a vertical staff with horizontal cross pieces and vertical plumb - lines . Ideally the process started in the centre of the planned camp at the site of the headquarters tent or building ( principia ) . Streets and other features were marked with coloured pennants or rods . Wall and ditch . The Castra ' s special structure also defended from attacks . The base ( " munimentum " , " fortification " ) was placed entirely within the " vallum " ( " wall " ) , which could be constructed under the protection of the legion in battle formation if necessary . The " vallum " was quadrangular aligned on the cardinal points of the compass . The construction crews dug a trench ( " fossa " ) , throwing the excavated material inward , to be formed into the rampart ( " agger " ) . On top of this a palisade of stakes ( " sudes " or " valli " ) was erected . The soldiers had to carry these stakes on the march . Over the course of time , the palisade might be replaced by a fine brick or stone wall , and the ditch serve also as a moat . A legion - sized camp always placed towers at intervals along the wall with positions between for the division artillery . Interval . Around the inside periphery of the " vallum " was a clear space , the " intervallum " , which served to catch enemy missiles , as an access route to the " vallum " and as a storage space for cattle ( " capita " ) and booty ( " praeda " ) . Legionaries were quartered in a peripheral zone inside the " intervallum " , which they could rapidly cross to take up position on the " vallum " . Inside of the legionary quarters was a peripheral road , the " Via Sagularis " , probably " service road " , as the " sagum " , a kind of cloak , was the garment of slaves . Streets , gates and central plaza . Every camp included " main street " , which ran unimpeded through the camp in a north - south direction and was very wide . The names of streets in many cities formerly occupied by the Romans suggest that the street was called " cardo " or " Cardus Maximus " . This name applies more to cities than it does to ancient camps . Typically " main street " was the " via principalis " . The central portion was used as a parade ground and headquarters area . The " headquarters " building was called the " praetorium " because it housed the " praetor " or base commander ( " first officer " ) , and his staff . In the camp of a full legion he held the rank of " consul " or " proconsul " but officers of lesser ranks might command . On one side of the " praetorium " was the " quaestorium " , the building of the supply officer , or " quaestor " ( " seeker " ) . On the other side was the " forum " , a small duplicate of an urban forum , where public business could be conducted . Along the " Via Principalis " were the homes or tents of the several " tribunes " in front of the barracks of the units they commanded . The " Via Principalis " went through the " vallum " in the " Porta Principalis Dextra " ( " right principal gate " ) and " Porta Principalis Sinistra " ( " left , etc . " ) , which were gates fortified with " turres " ( " towers " ) . Which was on the north and which on the south depends on whether the praetorium faced east or west , which remains unknown . The central region of the " Via Principalis " with the buildings for the command staff was called the " Principia " ( plural of " principium " ) . It was actually a square , as across this at right angles to the " Via Principalis " was the " Via Praetoria " , so called because the " praetorium " interrupted it . The " Via Principalis " and the " Via Praetoria " offered another division of the camp into four quarters . Across the central plaza ( " principia " ) to the east or west was the main gate , the " Porta Praetoria " . Marching through it and down " headquarters street " a unit ended up in formation in front of the headquarters . The standards of the legion were located on display there , very much like the flag of modern camps . On the other side of the praetorium the " Via Praetoria " continued to the wall , where it went through the " Porta Decumana " . In theory this was the back gate . Supplies were supposed to come in through it and so it was also called , descriptively , the " Porta Quaestoria " . The term Decumena , " of the 10th " , came from the arranging of " manipuli " or " turmae " from the first to the 10th , such that the 10th was near the " intervallum " on that side . The " Via Praetoria " on that side might take the name " Via Decumena " or the entire " Via Praetoria " be replaced with " Decumanus Maximus " . Canteen . In peaceful times the camp set up a marketplace with the natives in the area . They were allowed into the camp as far as the units numbered 5 ( half - way to the praetorium ) . There another street crossed the camp at right angles to the " Via Decumana " , called the " Via Quintana " , " 5th street " . If the camp needed more gates , one or two of the " Porta Quintana " were built , presumably named " dextra " and " sinistra " . If the gates were not built , the " Porta Decumana " also became the " Porta Quintana " . At " 5th street " a public market was allowed . Major buildings . The " Via Quintana " and the " Via Principalis " divided the camp into three districts : the " Latera Praetorii " , the " Praetentura " and the " Retentura " . In the " latera " ( " sides " ) were the " Arae " ( sacrificial altars ) , the " Augur atorium " ( for auspice s ) , the " Tribunal " , where courts martial and arbitrations were conducted ( it had a raised platform ) , the guardhouse , the quarters of various kinds of staff and the storehouses for grain ( " horrea " ) or meat ( " carnarea " ) . Sometimes the " horrea " were located near the barracks and the meat was stored on the hoof . Analysis of sewage from latrines indicates the legionary diet was mainly grain . Also located in the " Latera " was the " Armamentarium " , a long shed containing any heavy weapons and artillery not on the wall . The " Praetentura " ( " stretching to the front " ) contained the " Scamnum Legatorum " , the quarters of officers who were below general but higher than company commanders ( " Legati " ) . Near the " Principia " were the " Valetudinarium " ( hospital ) , " Veterinarium " ( for horses ) , " Fabrica " ( " workshop " , metals and wood ) , and further to the front the quarters of special forces . These included " Classici " ( " marines " , as most European camps were on rivers and contained a river naval command ) , " Equites " ( " cavalry " ) , " Exploratores " ( " scouts " ) , and " Vexillarii " ( carriers of vexillae , the official pennants of the legion and its units ) . Troops who did not fit elsewhere also were there . The part of the " Retentura " ( " stretching to the rear " ) closest to the " Principia " contained the " Quaestorium " . By the late empire it had developed also into a safekeep for plunder and a prison for hostages and high - ranking enemy captives . Near the " Quaestorium " were the quarters of the headquarters guard ( " Statores " ) , who amounted to two centuries ( companies ) . If the " Imperator " was present they served as his bodyguard . Barracks . Further from the " Qaestorium " were the tents of the " Nationes " ( " natives " ) , who were auxiliaries of foreign troops , and the legionaries themselves in double rows of tents or barracks ( " Strigae " ) . One " Striga " was as long as required and 18 m wide . In it were two " Hemistrigia " of facing tents centered in its 9 m strip . Arms could be stacked before the tents and baggage carts kept there as well . Space on the other side of the tent was for passage . In the northern places like Britain , where it got cold in the winter , they would make wood or stone barracks . The Romans would also put a fireplace in the barracks . They had about three bunk beds in it . They had a small room beside it where they put their armour ; it was as big as the tents . They would also make these barracks if the fort they had was going to stay there for good . A tent was 3 by 3 . 5 metres ( 0 . 6 m for the aisle ) , ten men per tent . Ideally a company took 10 tents , arranged in a line of 10 companies , with the 10th near the " Porta Decumana " . Of the c . 9 . 2 square metres of bunk space each man received 0 . 9 , or about 0 . 6 by 1 . 5 m , which was only practical if they slept with heads to the aisle . The single tent with its men was called " contubernium " , also used for " squad " . A squad during some periods was 8 men or fewer . The " Centurio " , or company commander , had a double - sized tent for his quarters , which served also as official company area . Other than there , the men had to find other places to be . To avoid mutiny , it became extremely important for the officers to keep them busy . A covered portico might protect the walkway along the tents . If barracks had been constructed , one company was housed in one barracks building , with the arms at one end and the common area at the other . The company area was used for cooking and recreation , such as gaming . The army provisioned the men and had their bread ( " panis militaris " ) baked in outdoor ovens , but the men were responsible for cooking and serving themselves . They could buy meals or supplementary foods at the canteen . The officers were allowed servants . Sanitation . For sanitary facilities , a camp had both public and private latrines . A public latrine consisted of a bank of seats situated over a channel of running water . One of the major considerations for selecting the site of a camp was the presence of running water , which the engineers diverted into the sanitary channels . Drinking water came from wells ; however , the larger and more permanent bases featured the " aqueduct " , a structure running a stream captured from high ground ( sometimes miles away ) into the camp . The praetorium had its own latrine , and probably the quarters of the high - ranking officers . In or near the " intervallum " , where they could easily be accessed , were the latrines of the soldiers . A public bathhouse for the soldiers , also containing a latrine , was located near or on the " Via Principalis " . Territory . The influence of a base extended far beyond its walls . The total land required for the maintenance of a permanent base was called its " territoria " . In it were located all the resources of nature and the terrain required by the base : pastures , woodlots , water sources , stone quarries , mines , exercise fields and attached villages . The central castra might also support various fortified adjuncts to the main base , which were not in themselves self - sustaining ( as was the base ) . In this category were " speculae " , " watchtowers " , " castella " , " small camps " , and naval bases . All the major bases near rivers featured some sort of fortified naval installation , one side of which was formed by the river or lake . The other sides were formed by a polygonal wall and ditch constructed in the usual way , with gates and watchtowers . The main internal features were the boat sheds and the docks . When not in use , the boats were drawn up into the sheds for maintenance and protection . Since the camp was placed to best advantage on a hill or slope near the river , the naval base was usually outside its walls . The " classici " and the " optiones " of the naval installation relied on the camp for its permanent defense . Naval personnel generally enjoyed better quarters and facilities . Many were civilians working for the military . Modifications in practice . This ideal was always modified to suit the terrain and the circumstances . Each camp discovered by archaeology has its own specific layout and architectural features , which makes sense from a military point of view . If , for example , the camp was built on an outcrop , it followed the lines of the outcrop . The terrain for which it was best suited and for which it was probably designed in distant prehistoric times was the rolling plain . The camp was best placed on the summit and along the side of a low hill , with spring water running in rivulets through the camp ( " aquatio " ) and pastureland to provide grazing ( " pabulatio " ) for the animals . In case of attack , arrows , javelins and sling missiles could be fired down at an enemy tiring himself to come up . For defence troops could be formed in an " acies " , or " battle - line " , outside the gates , where they could be easily resupplied and replenished , as well as being supported by archery from the palisade . The streets , gates and buildings present depended on the requirements and resources of the camp . The gates might vary from two to six and not be centred on the sides . Not all the streets and buildings might be present . Quadrangular camps in later times . Many settlements in Europe originated as Roman military camps and still show traces of their original pattern ( e . g . Castres in France , Barcelona in Spain ) . The pattern was also used by Spanish colonizers in America following strict rules by the Spanish monarchy for founding new cities in the New World . Many of the towns of England still retain forms of the word " castra " in their names , usually as the suffixes " - caster " or " - chester " - - Lancaster , Tadcaster , Chester , Manchester and Ribchester , for example . Castle has the same derivation , from the diminutive " castellum " or " little fort " . Camp life . Activities conducted in a castra can be divided into ordinary and " the duty " or " the watch " . Ordinary activity was performed during regular working hours . The duty was associated with operating the installation as a military facility . For example , none of the soldiers were required to man the walls all the time , but round - the clock duty always required a portion of the soldiers to be on duty at any time . Duty time was divided into " vigilia " , the eight watches into which the 24 - hour day was divided so they stood guard for 3 hours that day . The Romans used signals on brass instruments to mark time . These were mainly the " buccina " or " bucina " , the " cornu " and the " tuba " . As they did not possess valves for regulating the pitch , the range of these instruments was somewhat limited . Nevertheless the musicians ( " Aenatores " , " brassmen " ) managed to define enough signals for issuing commands . The instrument used to mark the passage of a watch was the " buccina " , from which the trumpet derives . It was sounded by a " buccinator " . Ordinary life . Ordinary camp life began with a " buccina " call at daybreak , the first watch of the day . The soldiers arose at this time and shortly after collected in the company area for breakfast and assembly . The centurion s were up before them and off to the " Principia " where they and the " Equites " were required to assemble . The regimental commanders , the " Tribunes " , were already converging on the " Praetorium " . There the general staff was busily at work planning the day . At a staff meeting the " Tribunes " received the password and the orders of the day . They brought those back to the " Centuriones " , who returned to their company areas to instruct the men , already breakfasted . For soldiers , the main item of the agenda was a vigorous training session lasting about a watch long . Recruits received two , one in the morning and one in the afternoon . Planning and supervision of training were under a general staff officer , who might manage training at several camps . According to Vegetius , the men might take a 32 km hike or a 6 to 8 kilometres jog under full pack , or swim a river . Marching drill was always in order . Each soldier was taught the use of every weapon and also was taught to ride . Seamanship was taught at naval bases . Soldiers were generalists in the military and construction arts . They practiced archery , spear - throwing and above all swordmanship against posts ( " pali " ) fixed in the ground . Training was taken very seriously and was democratic . Ordinary soldiers would see all the officers training with them including the " Praetor " or the Emperor if he was in camp . Swordmanship lessons and use of the shooting range probably took place on the " campus " , a " field " outside the " castra " , from which English camp derives . Its surface could be lightly paved . Winter curtailed outdoor training . The general might in that case have sheds constructed , which served as field houses for training . There is archaeological evidence in one case of an indoor equestrian ring . Apart from the training , each soldier had a regular job on the base , of which there were a large variety from the various kinds of clerks to the craftsmen . Soldiers changed jobs frequently . The commander ' s policy was to have all the soldiers skilled in all the arts and crafts so that they could be as interchangeable as possible . Even then the goal was not entirely achievable . The gap was bridged by the specialists , the " optiones " or " chosen men " , of which there were many different kinds . For example , a skilled artisan might be chosen to superintend a workshop . The supply administration was run as a business using money as the medium of exchange . The aureus was the preferred coin of the late republic and early empire ; in the late empire the solidus came into use . The larger bases , such as " Moguntiacum " , minted their own coins . As does any business , the base quaestorium required careful record keeping , performed mainly by the optiones . A chance cache of tablets from Vindolanda in Britain gives us a glimpse of some supply transactions . They record , among other things , the purchase of consumables and raw supplies , the storage and repair of clothing and other items , and the sale of items , including foodstuffs , to achieve an income . Vindolanda traded vigorously with the surrounding natives . Another feature of the camp was the military hospital ( " valetudinarium " , later " hospitium " ) . Augustus instituted the first permanent medical corps in the Roman army . Its physicians , the " medici ordinarii " , had to be qualified physicians . They were allowed medical students , practitioners and whatever orderlies they needed ; i . e . , the military hospitals were medical schools and places of residency as well . Officers were allowed to marry and to reside with their families on base . The army could not extend the same privileges to the men , who were not allowed to marry . However , they often kept common law families off base in communities nearby . The communities might be native , as the tribesmen tended to build around a permanent base for purposes of trade , but also the base sponsored villages ( " vici " ) of dependents and businessmen . Dependants were not allowed to follow an army on the march into hostile territory . An enlistment was for about 25 years . At the end of that time the veteran was given a " diploma " , or certificate of honorable discharge ( " honesta missio " ) . Some of these have survived engraved on stone . Typically they certify that the veteran , his wife ( one per veteran ) and children or his sweetheart were now Roman citizens , which is a good indication that troops , which were used chiefly on the frontier , were from peoples elsewhere on the frontier who wished to earn Roman citizenship . However , under Antoninus Pius , citizenship was no longer granted to the children of rank - and - file veterans , the privilege becoming restricted only to officers . Veterans often went into business in the communities near a base . They became permanent members of the community and would stay on after the troops were withdrawn , as in the notable case of St . Patrick ' s family . Duties . Conducted in parallel with the ordinary activities was " the duty " , the official chores required by the camp under strict military discipline . The " Legate " was ultimately responsible for them as he was for the entire camp , but he delegated the duty to a tribune chosen as officer of the day . The line " Tribunes " were commanders of " Cohort es " and were approximately the equivalent of colonels . The 6 tribunes were divided into units of two , with each unit being responsible for filling the position of officer of the day for two months . The two men of a unit decided among themselves who would take what day . They could alternate days or each take a month . One filled in for the other in case of illness . On his day , the tribune effectively commanded the camp and was even respected as such by the " Legate " . The equivalent concept of the duties performed in modern camps is roughly the detail . The responsibilities ( " curae " ) of the many kinds of detail were distributed to the men by all the methods considered fair and democratic : lot , rotation and negotiation . Certain kinds of " cura " were assigned certain classes or types of troops ; for example , wall sentries were chosen only from " Velites " . Soldiers could be temporarily or permanently exempted : the " immunes " . For example , a " Triarius " was " immunis " from the " curae " of the " Hastati " . The duty year was divided into time slices , typically one or two months , which were apportioned to units , typically maniple s or centuries . They were always allowed to negotiate who took the duty and when . The most common kind of " cura " were the posts of the sentinels , called the " excubiae " by day and the " vigilae " at night . Wall posts were " praesidia " , gate posts , " custodiae " , advance positions before the gates , " stationes " . In addition were special guards and details . One post was typically filled by four men , one sentinel and the others at ease until a situation arose or it was their turn to be sentinel . Some of the details were : List of castra . The street plan of various present - day cities still retains traces of a Roman camp , for example Marsala in Sicily , the ancient Lilybaeum , where the name of the main street - the Cassaro - perpetuates the name " castrum " . Due to an unbounded enthusiasm for local archaeology , the locations and layouts of Roman castra are rapidly becoming known . Both amateurs and professionals are involved in excavation and publication . Internet sites giving photographs and the texts of inscriptions are numerous . External links . Below are a number of links to sites reporting or summarizing current research or thinking . Many are reprints of articles made available to the public at no charge . The historical researcher will find their bibliographies of great interest .