Turma A turma ( Latin for " swarm , squadron " , plural " turmae " ) was a cavalry squadron in the Roman army of the Republic and Empire . In the Byzantine Empire , it became applied to the larger , regiment - sized military - cum - administrative divisions of a " thema " . Roman army . Republic . In the 3rd and 2nd centuries BC , the time of the Punic Wars and Rome ' s expansion into Spain and Greece , the core of the Roman army was formed by citizens , augmented by contingents from Rome ' s allies ( " socii " ) . The organization of the Roman legion of the period is described by the Greek historian Polybius ( cf . the so - called " Polybian army " ) , who writes that each 4 , 200 - strong infantry legion was accompanied by 300 citizen cavalry ( " equites " ) . This contingent was divided into ten " turmae " . According to Polybius , the squadron members would elect as their officers 3 " decuriones " ( " leaders of 10 men " ) , of whom the first to be chosen would act as the squadron ' s commander and the other two as his deputies . As in earlier times , these men were drawn from among the 18 " centuria e " of the equestrian order , the wealthiest classes of the Roman people , who could afford to provide for the horse and its equipment themselves . Empire . With the reorganization of the army under Emperor Augustus ( r . 27 BC – 14 AD ) and his successors , the " turma " became the basic sub - unit of the cavalry , the rough equivalent of the infantry " centuria " , both in the auxiliaries , who formed the bulk of the Roman cavalry , and in the legionary cavalry detachments . The auxiliary " cohors equitata " was a mixed unit combining infantry and cavalry , and existed in two types : the " cohors equitata quingenaria " , with an infantry cohort of 480 men and 4 " turmae " of cavalry , and the reinforced " cohors equitata milliaria " , with 800 infantry and 8 " turmae " . Likewise , the purely cavalry " alae " contained either 16 ( " ala quingenaria " ) or 24 " turmae " ( " ala milliaria " ) . Individual " turmae " of camel - riders ( " dromedarii " ) also appear among " cohortes equitatae " in the Middle East , and Emperor Trajan ( r . 98 – 117 ) established the first all - camel cavalry unit , the " Ala I Ulpia dromedariorum Palmyrenorum " . The " turma " was still commanded by a " decurio " , aided by two subaltern " principales " ( under - officers ) , a " sesquiplicarius " ( soldier with one - and - a - half times pay ) and a " duplicarius " ( soldier with double pay ) , as well as a " signifer " or " vexillarius " ( a standard - bearer , cf . " vexillum " ) . These ranks corresponded respectively with the infantry ' s " tesserarius " ( officer of the watch ) , " optio " , and " signifer " . The exact size of the " turma " under the Principate , however , is unclear : 30 men was the norm in the Republican army and apparently in the " cohortes equitatae " , but not for the " alae " . The " De Munitionibus Castrorum " , for instance , records that a " cohors equitata milliaria " numbered exactly 240 troopers , i . e . 30 men per " turma " , but also gives the number of horses for the " ala milliaria " , composed of 24 " turmae " , at 1000 . If one subtracts the extra horses of the officers ( two for a " decurio " , one for each of the two subaltern under - officers ) , one is left with 832 horses , which does not divide evenly with 24 . At the same time , Arrian explicitly says that the " ala quingenaria " counted 512 men , suggesting a size of 32 men for each " turma " . As for the legions , during the Principate , each had a cavalry contingent organized in four " turmae " . A legionary " turma " was led by a centurion , assisted by an " optio " and a " vexillarius " as senior " principales " . Each of them led a file of ten troopers , for a grand total of 132 horsemen in each legion . Their status was distinctly inferior to that of the legionary infantry : the centurions and " principales " of the legionary " turmae " were classed as " supernumerarii " and although their men were included in the legionary cohort lists , they camped separately from them . In the late Roman army , the " turma " and its structure were retained , with changes in titelature only : the " turma " was still headed by a " decurio " , who also led the first ten - strong file , while the other two files were led by subaltern " catafractarii " , in essence the successors of the early Empire ' s " duplicarii " and " sesquiplicarii " . Traces of this structure also apparently survived in the 6th - century East Roman army : in the late - 6th - century " Strategikon of Maurice " , the cavalry files are led by a " dekarchos " ( , " leader of ten " ) . Byzantine Empire . In the 7th century , as a result of the crisis caused by the Muslim conquests , the Byzantine military and administrative system was reformed : the old late Roman division between military and civil administration was abandoned , and the remains of the East Roman army ' s field armies were settled in great districts , the " thema ta " , that were named after them . The term " turma " , in its Greek transcription " tourma " ( τούρμα or ) , reappears at that time as the major subdivision of a " thema " . The army of each " thema " ( except for the Optimatoi ) was divided into two to four " tourmai " , and each " tourma " further into a number of " moirai " ( μοίραι ) or " droungoi " ( ) , which in turn were composed of several " banda " ( singular : " bandon " , βάνδον , from , " banner " ) . This division was carried through to the territorial administration of each " thema " : " tourmai " and " banda " ( but not the " moirai " / " droungoi " ) were identified with clearly defined districts which served as their garrison and recruitment areas . In his " Taktika " , Emperor Leo VI the Wise ( r . 886 – 912 ) presents an idealized " thema " as consisting of three " tourmai " , each divided into three " droungoi " , etc . This picture , however , is misleading , as the sources do not support any degree of uniformity in size or number of subdivisions in the different " themata " , nor indeed an exact correspondence of the territorial with the tactical divisions : depending on the tactical exigencies , smaller administrative " tourmai " could be joined together on campaign and larger ones broken up . Since the elementary unit , the " bandon " , could itself number between 200 and 400 men , the " tourma " too could reach up to 6 , 000 men , although 2 , 000 – 5 , 000 seems to have been the norm between the seventh and early tenth centuries . Each " tourma " was usually headed by a tourmarchēs ( τουρμάρχης , " commander of a " tourma " " ) . In some cases , however , an " ek prosōpou " , a temporary representative of the governing " stratēgos " of each " thema " , could be appointed instead . The title first appears in circa 626 , when a certain George was " tourmarchēs " of the " Armeniakoi " . The " tourmarchēs " was usually based in a fortress town . Aside from his military responsibilities , he exercised fiscal and judicial duties in the area under his control . In the lists of offices ( " Taktika " ) and seals , " tourmarchai " usually hold the ranks of " spatharokandidatos " , " spatharios " or " kandidatos " . In function and rank , the " tourmarchēs " corresponded with the " topotērētēs " of the professional imperial " tagma ta " regiments . The " tourmarchai " were paid according to the importance of their " thema " : those of the more prestigious Anatolian themes received 216 gold " nomismata " annually , while those of the European themes received 144 " nomismata " , the same amount paid to the " droungarioi " and the other senior officers of the " thema " . In some sources , the earlier term " merarchēs " ( μεράρχης , " commander of a " meros " , division " ) , which occupied a similar hierarchical position in the 6th – 7th centuries , is used interchangeably with " tourmarchēs " . In the 9th – 10th centuries , it is often found in the variant form " meriarchēs " ( μεριάρχης ) . It has , however , also been suggested by scholars like John B . Bury and John Haldon that the latter was a distinct post , held by the " tourmarchēs " attached to the governing " stratēgos " of each " thema " and residing at the thematic capital . In the mid - 10th century , the average size of most units fell . In the case of the " tourma " , it dropped from 2 , 000 – 3 , 000 men to 1 , 000 men and less , in essence to the level of the earlier " droungos " , although larger " tourmai " are still recorded . It is probably no coincidence that the term " " droungos " " disappears from use at around that time . Consequently , the " tourma " was divided directly into five to seven " banda " , each of 50 – 100 cavalry or 200 – 400 infantry . The term " tourma " itself fell gradually into disuse in the 11th century , but survived at least until the end of the 12th century as an administrative term . " Tourmarchai " are still attested in the first half of the 11th century , but the title seems to have fallen out of use thereafter .