← Latin for Soldiers, Sailors and Military Strategists
The irregular verb possum (I am able, I can) is one of the most important and frequently used verbs in Latin military contexts. It combines the verb sum (to be) with the prefix pot- (from potis, meaning "able" or "powerful"), creating a compound that expresses capability, possibility, and power.
Definition: possum is an irregular verb meaning "to be able," "can," or "to have power." It expresses physical ability, permission, possibility, or opportunity.
Q: What does possum mean in Latin? A: Possum means "I am able" or "I can" in Latin. It's an irregular verb that combines with infinitives to express what someone is able to do.
In this lesson, possum will appear in various military contexts showing how Roman commanders, soldiers, and sailors expressed their abilities, limitations, and strategic possibilities. The verb will be used with complementary infinitives and in different tenses to demonstrate tactical capabilities and constraints.
Subject: Latin Language Learning Level: Beginner to Intermediate Focus: Military Latin Vocabulary and Grammar Lesson Type: Reading Comprehension with Grammar Instruction Target Audience: English-speaking autodidacts learning Latin
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possum is irregular and combines pot- with forms of sum -
It requires a complementary infinitive to complete its meaning -
In military contexts, it often expresses strategic capabilities -
The perfect stem is potu-, making potuī (I was able) -
Negative forms with nōn possum express impossibility or inability
23.1 Mīlitēs soldiers nostrī our hostēs enemies superāre to overcome possunt are able
23.2 Nōn not possumus we are able flūmen river trānsīre to cross sine without nāvibus ships
23.3 Dux leader exercitum army dūcere to lead potest is able per through montēs mountains
23.4 Potestne is able? legiō legion urbem city capere to capture hodiē today
23.5 Nautae sailors mare sea nāvigāre to sail nōn not potuērunt were able propter because of tempestātem storm
23.6 Sī if possēmus we were able castra camp mūnīre to fortify celerīter quickly
23.7 Hostēs enemies vincere to conquer nōs us numquam never poterunt will be able
23.8 Caesar Caesar ipse himself mīlitēs soldiers hortārī to encourage potuit was able
23.9 Quis who potest is able arma weapons ferre to carry tam so gravia heavy
23.10 Equitēs cavalry fugere to flee possunt are able velocius more swiftly quam than peditēs infantry
23.11 Nēmō no one resistere to resist potest is able tantīs such great cōpiīs forces
23.12 Potuistīne were you able? vidēre to see sīgna standards hostium of enemies
23.13 Centuriō centurion suōs his own servāre to save nōn not poterat was able
23.14 Multī many pugnāre to fight diūtius longer nōn not poterant were able
23.15 Sōlus alone dux leader cōnsilium plan mūtāre to change potest is able
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23.1 Mīlitēs nostrī hostēs superāre possunt. Our soldiers can overcome the enemies.
23.2 Nōn possumus flūmen trānsīre sine nāvibus. We cannot cross the river without ships.
23.3 Dux exercitum dūcere potest per montēs. The leader can lead the army through the mountains.
23.4 Potestne legiō urbem capere hodiē? Can the legion capture the city today?
23.5 Nautae mare nāvigāre nōn potuērunt propter tempestātem. The sailors could not sail the sea because of the storm.
23.6 Sī possēmus castra mūnīre celerīter! If only we could fortify the camp quickly!
23.7 Hostēs vincere nōs numquam poterunt. The enemies will never be able to conquer us.
23.8 Caesar ipse mīlitēs hortārī potuit. Caesar himself was able to encourage the soldiers.
23.9 Quis potest arma ferre tam gravia? Who can carry such heavy weapons?
23.10 Equitēs fugere possunt velocius quam peditēs. The cavalry can flee more swiftly than the infantry.
23.11 Nēmō resistere potest tantīs cōpiīs. No one can resist such great forces.
23.12 Potuistīne vidēre sīgna hostium? Were you able to see the enemy standards?
23.13 Centuriō suōs servāre nōn poterat. The centurion was not able to save his men.
23.14 Multī pugnāre diūtius nōn poterant. Many were not able to fight longer.
23.15 Sōlus dux cōnsilium mūtāre potest. Only the leader can change the plan.
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23.1 Mīlitēs nostrī hostēs superāre possunt.
23.2 Nōn possumus flūmen trānsīre sine nāvibus.
23.3 Dux exercitum dūcere potest per montēs.
23.4 Potestne legiō urbem capere hodiē?
23.5 Nautae mare nāvigāre nōn potuērunt propter tempestātem.
23.6 Sī possēmus castra mūnīre celerīter!
23.7 Hostēs vincere nōs numquam poterunt.
23.8 Caesar ipse mīlitēs hortārī potuit.
23.9 Quis potest arma ferre tam gravia?
23.10 Equitēs fugere possunt velocius quam peditēs.
23.11 Nēmō resistere potest tantīs cōpiīs.
23.12 Potuistīne vidēre sīgna hostium?
23.13 Centuriō suōs servāre nōn poterat.
23.14 Multī pugnāre diūtius nōn poterant.
23.15 Sōlus dux cōnsilium mūtāre potest.
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The verb possum is irregular because it combines the prefix pot- with forms of sum. When pot- comes before a vowel, it remains pot-; before consonants, it becomes pos-.
Present Tense: -
possum (I am able) -
potes (you are able) -
potest (he/she/it is able) -
possumus (we are able) -
potestis (you all are able) -
possunt (they are able)
Imperfect Tense: -
poteram (I was able) -
poterās (you were able) -
poterat (he/she/it was able) -
poterāmus (we were able) -
poterātis (you all were able) -
poterant (they were able)
Future Tense: -
poterō (I will be able) -
poteris (you will be able) -
poterit (he/she/it will be able) -
poterimus (we will be able) -
poteritis (you all will be able) -
poterunt (they will be able)
Perfect Tense: -
potuī (I was able/have been able) -
potuistī (you were able) -
potuit (he/she/it was able) -
potuimus (we were able) -
potuistis (you all were able) -
potuērunt (they were able)
Present Subjunctive: -
possim, possīs, possit, possīmus, possītis, possint
Imperfect Subjunctive: -
possem, possēs, posset, possēmus, possētis, possent
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Forgetting the complementary infinitive: possum requires an infinitive to complete its meaning. Never use possum alone. -
Wrong: Mīlitēs possunt. -
Right: Mīlitēs pugnāre possunt. (The soldiers are able to fight.) -
Confusing pot-/pos- alternation: Remember that pot- appears before vowels, pos- before consonants. -
potest (not posest) -
possunt (not potsunt) -
Using the wrong perfect stem: The perfect stem is potu-, not poss-. -
potuī (not possuī) -
Word order with infinitive: While Latin is flexible, the infinitive often precedes possum for emphasis on the action.
Unlike English "can," which is a modal verb, Latin possum is a full verb that requires an infinitive. English speakers often forget the infinitive because English uses: -
"I can fight" But Latin requires: -
"Pugnāre possum" (literally: "to fight I am able")
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Identify the subject (who is able?) -
Choose the correct form of possum matching the subject -
Add the complementary infinitive (able to do what?) -
Place negative nōn before possum for "cannot" -
Remember word order is flexible but infinitive often comes first for emphasis
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For Roman military commanders, the concept of possum was central to strategic thinking. The ability or inability to perform certain actions determined the outcome of campaigns. Roman military writers frequently used possum to discuss:
Tactical Possibilities: Commanders assessed what their forces could achieve given terrain, supplies, and enemy strength. The phrase "quid possimus" (what we can do) appears frequently in military councils.
Logistical Limitations: Supply lines, river crossings, and mountain passes all presented challenges expressed through possum. Caesar's Commentaries are filled with assessments of what his legions could or could not accomplish.
Naval Capabilities: For Roman admirals, weather conditions severely limited what they could do. The phrase "nōn posse nāvigāre" (unable to sail) could doom entire campaigns.
Individual Prowess: Roman military culture valued individual capability. A soldier who "multum potest" (is very capable) earned promotion and honors.
The concept extended beyond physical ability to moral and legal authority. A general's "imperium" gave him the power (potestās) to command, directly related to possum. Without proper authority, even capable commanders "nōn possunt" legally lead troops.
Understanding possum helps modern readers grasp how Romans conceptualized military power not as abstract force but as concrete capabilities limited by real-world constraints.
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From Caesar, De Bello Gallico 1.31:
Caesar Caesar cum when id this nūntiātum having been reported esset it was, mātūrat he hastens ab from urbe the city proficīscī to set out et and quam as maximīs greatest potest he is able itineribus by marches in into Galliam Gaul ulteriōrem farther contendit he hurries et and ad to Genāvam Geneva pervenit. he arrives. Prōvinciae To the province tōtī whole quam as maximum greatest potest he is able mīlitum of soldiers numerum number imperat. he orders.
Caesar cum id nūntiātum esset, mātūrat ab urbe proficīscī et quam maximīs potest itineribus in Galliam ulteriōrem contendit et ad Genāvam pervenit. Prōvinciae tōtī quam maximum potest mīlitum numerum imperat.
When this had been reported to Caesar, he hastens to set out from the city and hurries into Farther Gaul by the greatest marches he can, and arrives at Geneva. He orders from the whole province the greatest number of soldiers he can.
Caesar cum id nūntiātum esset, mātūrat ab urbe proficīscī et quam maximīs potest itineribus in Galliam ulteriōrem contendit et ad Genāvam pervenit. Prōvinciae tōtī quam maximum potest mīlitum numerum imperat.
This passage showcases two important uses of potest in military contexts: -
"quam maximīs potest itineribus" - "by the greatest marches he can" shows possum with an implied infinitive (facere or īre understood). The superlative with quam and potest creates an expression of maximum capability. -
"quam maximum potest mīlitum numerum" - "the greatest number of soldiers he can" again uses the quam + superlative + potest construction, with an implied infinitive (imperāre or colligere).
Caesar's characteristic style employs possum to emphasize both urgency and the limits of practical possibility. The repetition of the construction emphasizes Caesar pushing capabilities to their maximum extent, a recurring theme in his military narrative.
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23.16 Lēgātus legate imperātōrī to commander scrībit writes sē himself oppidum town dēfendere to defend nōn not posse to be able diūtius longer
23.17 Obsidiōne by siege pressī pressed cīvēs citizens resistere to resist vix scarcely possunt are able iam now
23.18 Auxilia reinforcements mittere to send nōn not possumus we are able quod because hostēs enemies viās roads omnēs all clausērunt have closed
23.19 Frūmentum grain dēficit is lacking et and mīlitēs soldiers famem hunger patī to endure diūtius longer nōn not poterunt will be able
23.20 Sī if succurrere to help nōbīs us potestis you are able venīte come quam as celerrimē most quickly
23.21 Mūrōs walls reficere to repair temptāmus we try sed but hostium of enemies tēla missiles prohibent prevent nē lest id this facere to do possīmus we may be able
23.22 Aqua water in in oppidō town dēsinit is ceasing et and sitim thirst tolerāre to endure nōn not possumus we are able multō much diūtius longer
23.23 Dux leader hostium of enemies dīcit says sē himself nōs us vī by force expugnāre to storm posse to be able intrā within trēs three diēs days
23.24 Paucī few tantum only equitēs cavalry supersunt survive quī who litterās letters ferre to carry possint may be able per through hostium of enemies custōdiās guards
23.25 Vulnerātī wounded mīlitēs soldiers pugnāre to fight iam now nōn not possunt are able et and medicī doctors omnēs all labōrant are working diē by day noctūque and by night
23.26 Potesne are you able tū you ipse yourself cum with exercitū army venīre to come ad to nostrum our auxilium aid
23.27 Arma weapons et and sagittās arrows iam now dēsunt are lacking nec nor diūtius longer dēfendere to defend mūrōs walls possumus we are able
23.28 Sī if nōn not poteritis you will be able auxilium help ferre to bring celeriter quickly dēdere to surrender nōs ourselves hostibus to enemies cōgēmur we will be compelled
23.29 Senēs old men et and puerī boys arma weapons capere to take coāctī compelled sunt are quod because aliī others pugnāre to fight iam now nōn not possunt are able
23.30 Spērāmus we hope tamen however nōs us resistere to resist posse to be able dōnec until auxilium help vestrum your advenerit will have arrived
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23.16 Lēgātus imperātōrī scrībit sē oppidum dēfendere nōn posse diūtius. The legate writes to the commander that he cannot defend the town any longer.
23.17 Obsidiōne pressī cīvēs resistere vix possunt iam. The citizens, hard pressed by the siege, can scarcely resist any longer.
23.18 Auxilia mittere nōn possumus quod hostēs viās omnēs clausērunt. We cannot send reinforcements because the enemies have closed all the roads.
23.19 Frūmentum dēficit et mīlitēs famem patī diūtius nōn poterunt. Grain is running short and the soldiers will not be able to endure hunger much longer.
23.20 Sī succurrere nōbīs potestis, venīte quam celerrimē! If you can help us, come as quickly as possible!
23.21 Mūrōs reficere temptāmus sed hostium tēla prohibent nē id facere possīmus. We are trying to repair the walls but enemy missiles prevent us from being able to do it.
23.22 Aqua in oppidō dēsinit et sitim tolerāre nōn possumus multō diūtius. Water in the town is running out and we cannot endure thirst much longer.
23.23 Dux hostium dīcit sē nōs vī expugnāre posse intrā trēs diēs. The enemy leader says he can storm us by force within three days.
23.24 Paucī tantum equitēs supersunt quī litterās ferre possint per hostium custōdiās. Only a few cavalry survive who can carry letters through the enemy guards.
23.25 Vulnerātī mīlitēs pugnāre iam nōn possunt et medicī omnēs labōrant diē noctūque. The wounded soldiers can no longer fight and all the doctors are working day and night.
23.26 Potesne tū ipse cum exercitū venīre ad nostrum auxilium? Can you yourself come with the army to our aid?
23.27 Arma et sagittās iam dēsunt nec diūtius dēfendere mūrōs possumus. Weapons and arrows are now lacking nor can we defend the walls any longer.
23.28 Sī nōn poteritis auxilium ferre celeriter, dēdere nōs hostibus cōgēmur. If you cannot bring help quickly, we will be forced to surrender ourselves to the enemies.
23.29 Senēs et puerī arma capere coāctī sunt quod aliī pugnāre iam nōn possunt. Old men and boys have been forced to take up arms because others can no longer fight.
23.30 Spērāmus tamen nōs resistere posse dōnec auxilium vestrum advenerit. Nevertheless we hope we can resist until your help arrives.
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23.16 Lēgātus imperātōrī scrībit sē oppidum dēfendere nōn posse diūtius.
23.17 Obsidiōne pressī cīvēs resistere vix possunt iam.
23.18 Auxilia mittere nōn possumus quod hostēs viās omnēs clausērunt.
23.19 Frūmentum dēficit et mīlitēs famem patī diūtius nōn poterunt.
23.20 Sī succurrere nōbīs potestis, venīte quam celerrimē!
23.21 Mūrōs reficere temptāmus sed hostium tēla prohibent nē id facere possīmus.
23.22 Aqua in oppidō dēsinit et sitim tolerāre nōn possumus multō diūtius.
23.23 Dux hostium dīcit sē nōs vī expugnāre posse intrā trēs diēs.
23.24 Paucī tantum equitēs supersunt quī litterās ferre possint per hostium custōdiās.
23.25 Vulnerātī mīlitēs pugnāre iam nōn possunt et medicī omnēs labōrant diē noctūque.
23.26 Potesne tū ipse cum exercitū venīre ad nostrum auxilium?
23.27 Arma et sagittās iam dēsunt nec diūtius dēfendere mūrōs possumus.
23.28 Sī nōn poteritis auxilium ferre celeriter, dēdere nōs hostibus cōgēmur.
23.29 Senēs et puerī arma capere coāctī sunt quod aliī pugnāre iam nōn possunt.
23.30 Spērāmus tamen nōs resistere posse dōnec auxilium vestrum advenerit.
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This military dispatch demonstrates advanced uses of possum in urgent military communications:
Several examples show possum in the subjunctive mood: -
possīmus (23.21) - present subjunctive in a purpose clause with nē -
possint (23.24) - present subjunctive in a relative clause of characteristic -
posse (23.30) - present infinitive in indirect statement
Multiple examples show possum in accusative + infinitive constructions: -
sē...nōn posse (23.16) - "that he cannot" -
sē...posse (23.23) - "that he can" -
nōs...posse (23.30) - "that we can"
The dispatch uses temporal modifiers to emphasize urgency: -
diūtius (longer) - appears multiple times -
iam (now, already) - emphasizes present inability -
multō diūtius - "much longer" intensifies the time constraint
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Prohibitive constructions: "prohibent nē...possīmus" (23.21) shows how Romans expressed prevention of ability -
Conditional sentences: "Sī...potestis" (23.20) and "Sī nōn poteritis" (23.28) show future conditions affecting ability -
Causal clauses: "quod...nōn possunt" (23.29) explains why certain actions are necessary
The dispatch combines possum with military infinitives: -
dēfendere (to defend) -
resistere (to resist) -
pugnāre (to fight) -
expugnāre (to storm/assault) -
tolerāre (to endure)
This creates a precise military vocabulary expressing tactical capabilities and limitations crucial for command decisions.
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This lesson is part of the Latinum Institute's comprehensive Latin reading course, designed specifically for autodidacts learning Latin independently. The course has been developed by Evan der Millner BA MA (Cantab. NZ, London), who has been creating innovative online language learning materials since 2006.
The Latinum Institute's method, detailed at latinum.substack.com and latinum.org.uk, emphasizes: -
Extensive reading with carefully scaffolded texts -
Granular interlinear translations that reveal Latin structure -
Natural Latin word order based on authentic Roman authors -
Cultural and historical context integrated with language learning -
Progressive difficulty building from simple to complex constructions
Each lesson follows a consistent structure enabling self-directed learners to: -
Understand new vocabulary through contextualized examples -
See authentic Latin syntax patterns -
Grasp grammatical concepts through clear explanations -
Experience real Latin literature with supportive glossing -
Apply knowledge through varied genre exercises
The military focus in this series provides coherent thematic vocabulary while exposing learners to the Latin that shaped Western military terminology and strategic thinking.
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