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Welcome to Lesson 196 of the Latinum Institute Classical Latin Reading Course. In this lesson we turn our attention to the Latin cardinal numeral decem, meaning “ten.” This is one of the most foundational words in the Latin language — and indeed in the entire Indo-European family — with deep roots stretching back to Proto-Indo-European *déḱm̥. The reflexes of this root appear in nearly every daughter language: Greek δέκα (déka), Sanskrit दश (dáśa), Gothic taíhun, Old English tīen (whence modern English “ten”), and many more.
In Latin, decem is an indeclinable cardinal numeral. Unlike many Latin words, it does not change form for case, gender, or number — it remains decem in every syntactic position. This simplicity is deceptive, however, for the influence of decem radiates through an enormous family of derived words: decimus, -a, -um (tenth), decimō, -āre (to tithe, to decimate), December (originally the tenth month of the old Roman calendar beginning in March), decuria (a group of ten), decuriō (a commander of ten), and the compound numerals ūndecim (eleven, literally “one-and-ten”), duodecim (twelve), and so on up to ūndēvīgintī (nineteen).
The Roman numeral system represented ten with the symbol X, and the decimal structure of Roman counting, military organization, and administrative systems all centered on this number. The Roman legion organized its cavalry into decuriae of ten horsemen; the infamous punishment of decimātiō involved executing every tenth soldier; and the decemvirī were the board of ten men who codified the Twelve Tables of Roman law.
Frequently Asked Question: What does decem mean in Classical Latin?
Decem is the Latin cardinal numeral for “ten.” It is indeclinable, meaning it never changes form regardless of the grammatical context. It governs a plural noun and any adjectives agreeing with that noun take plural forms appropriate to the noun’s gender and case. The word descends from Proto-Indo-European *déḱm̥ and is cognate with English “ten,” Greek δέκα, and Sanskrit दश.
Key Takeaways: -
Decem is indeclinable — it has one single form for all cases and genders. -
It governs plural nouns: decem virī (ten men), decem nāvēs (ten ships), decem verba (ten words). -
It generates a vast family of derivatives: decimus, decimō, December, decuria, decemvirī. -
The Roman numeral X represents decem. -
In compound numerals, decem appears as -decim: ūndecim (11), duodecim (12), trēdecim (13), etc.
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decem [ˈde.kem] — stress falls on the first syllable. The c before e is pronounced as a hard [k] in Classical Latin, not as the [tʃ] of Ecclesiastical pronunciation. The final -m was likely nasalized or weakly articulated in connected speech.
decimus [ˈde.ki.mʊs] — “tenth”; three syllables, stress on the first.
duodecim [ˈdʊ.o.de.kim] — “twelve”; four syllables, stress on the first. Note the diphthong uo in Classical pronunciation.
ūndecim [ˈuːn.de.kim] — “eleven”; three syllables, stress on the first. The ū is long.
decuria [deˈkʊ.ri.a] — “a group of ten”; four syllables, stress on the second.
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196.1 Decem ten virī men vēnērunt came.
196.2 Rēx the king decem ten equōs horses habēbat was having.
196.3 Decem ten annōs years Trōiam Troy oppugnāvērunt they attacked.
196.4 Mīlitēs the soldiers decem ten mīlia thousands passuum of paces ambulāvērunt walked.
196.5 In in urbe the city decem ten templa temples erant were.
196.6 Magister the teacher decem ten puerōs boys docēbat was teaching.
196.7 Caesar Caesar decem ten legiōnēs legions in into Galliam Gaul dūxit led.
196.8 Nāvis the ship decem ten diēs days in in marī the sea erat was.
196.9 Decem ten ex out of illīs those captī captured sunt were.
196.10 Senātus the senate decem ten lēgātōs legates ad to rēgem the king mīsit sent.
196.11 Decemvirī the ten men lēgēs laws duodecim twelve tabulārum of tables scrīpsērunt wrote.
196.12 Post after decem ten annōs years bellī of war Graecī the Greeks tandem at last domum home rediērunt returned.
196.13 Ā from decimō the tenth mīlite soldier usque all the way ad to vīcēsimum the twentieth omnēs all fortiōrēs braver erant were.
196.14 Decem ten mēnsēs months sunt are ab from Mārtiō March ad to Decembrem December sī if utrumque both inclūdis you include.
196.15 Dux the leader decem ten cohortēs cohorts in in aciē the line prīmā first collocāvit stationed et and cēterās the others post after eās them instrūxit arranged.
196.1 Decem virī vēnērunt. → “Ten men came.”
196.2 Rēx decem equōs habēbat. → “The king had ten horses.”
196.3 Decem annōs Trōiam oppugnāvērunt. → “They besieged Troy for ten years.”
196.4 Mīlitēs decem mīlia passuum ambulāvērunt. → “The soldiers marched ten thousand paces.”
196.5 In urbe decem templa erant. → “In the city there were ten temples.”
196.6 Magister decem puerōs docēbat. → “The teacher was instructing ten boys.”
196.7 Caesar decem legiōnēs in Galliam dūxit. → “Caesar led ten legions into Gaul.”
196.8 Nāvis decem diēs in marī erat. → “The ship was at sea for ten days.”
196.9 Decem ex illīs captī sunt. → “Ten of those men were captured.”
196.10 Senātus decem lēgātōs ad rēgem mīsit. → “The senate sent ten envoys to the king.”
196.11 Decemvirī lēgēs duodecim tabulārum scrīpsērunt. → “The Board of Ten wrote the laws of the Twelve Tables.”
196.12 Post decem annōs bellī Graecī tandem domum rediērunt. → “After ten years of war, the Greeks at last returned home.”
196.13 Ā decimō mīlite usque ad vīcēsimum omnēs fortiōrēs erant. → “From the tenth soldier all the way to the twentieth, all were braver.”
196.14 Decem mēnsēs sunt ab Mārtiō ad Decembrem sī utrumque inclūdis. → “There are ten months from March to December if you count both ends.”
196.15 Dux decem cohortēs in aciē prīmā collocāvit et cēterās post eās instrūxit. → “The commander stationed ten cohorts in the front line and drew up the rest behind them.”
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196.1 Decem virī vēnērunt.
196.2 Rēx decem equōs habēbat.
196.3 Decem annōs Trōiam oppugnāvērunt.
196.4 Mīlitēs decem mīlia passuum ambulāvērunt.
196.5 In urbe decem templa erant.
196.6 Magister decem puerōs docēbat.
196.7 Caesar decem legiōnēs in Galliam dūxit.
196.8 Nāvis decem diēs in marī erat.
196.9 Decem ex illīs captī sunt.
196.10 Senātus decem lēgātōs ad rēgem mīsit.
196.11 Decemvirī lēgēs duodecim tabulārum scrīpsērunt.
196.12 Post decem annōs bellī Graecī tandem domum rediērunt.
196.13 Ā decimō mīlite usque ad vīcēsimum omnēs fortiōrēs erant.
196.14 Decem mēnsēs sunt ab Mārtiō ad Decembrem sī utrumque inclūdis.
196.15 Dux decem cohortēs in aciē prīmā collocāvit et cēterās post eās instrūxit.
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These are the grammar rules for decem in Classical Latin:
1. Indeclinability of Cardinal Numerals
The cardinal numerals from quattuor (4) through centum (100) are indeclinable in Classical Latin. This means decem never changes form. It does not decline for case, gender, or number. Compare this with the lower cardinals: ūnus, -a, -um (one) declines like a first/second declension adjective; duo, duae, duo (two) has its own irregular declension; trēs, tria (three) declines as a third-declension adjective. But from four onward, the cardinals are frozen forms.
Thus: decem virī (ten men, nominative), decem virōrum (of ten men, genitive), decem virīs (to/for ten men, dative), decem virōs (ten men, accusative), decem virīs (by/with/from ten men, ablative). In every case, decem remains unchanged — only the noun it modifies shows case inflection.
2. Agreement with Plural Nouns
Because decem inherently denotes a plural quantity, it always accompanies plural nouns. Any adjective modifying the same noun takes its normal plural agreement: decem virī fortēs (ten brave men), decem nāvēs longae (ten warships), decem oppida magna (ten large towns). The adjectives agree with the noun in case, number, and gender as usual — decem itself simply sits alongside them without inflecting.
3. The Accusative of Duration
Several examples in this lesson illustrate the accusative of extent of time (also called the accusative of duration): decem annōs (for ten years), decem diēs (for ten days). Latin uses the bare accusative — without any preposition — to express how long an action lasted. English typically requires “for” before the time expression, but Latin does not. This is a standard and very common construction: Trōiam decem annōs oppugnāvērunt = “They besieged Troy for ten years.”
4. Mīlia as a Neuter Noun
In example 196.4, decem mīlia passuum (ten thousand paces) illustrates an important point. While mīlle (one thousand) is an indeclinable adjective in Classical Latin (mīlle mīlitēs = a thousand soldiers), its plural mīlia is a neuter noun of the third declension. It therefore takes a partitive genitive: decem mīlia passuum = literally “ten thousands of paces.” The noun mīlia can itself be modified by adjectives and declined: decem mīlium passuum (genitive), decem mīlibus passuum (dative/ablative).
5. Compound Numerals with -decim
When decem forms the second element of compound numerals from eleven to nineteen, it appears as -decim: ūndecim (11), duodecim (12), trēdecim (13), quattuordecim (14), quīndecim (15), sēdecim (16), septendecim (17), duodēvīgintī (18, literally “two-from-twenty”), ūndēvīgintī (19, literally “one-from-twenty”). Note that 18 and 19 are formed by subtraction from twenty rather than addition to ten — a distinctive feature of Latin numeral formation.
6. The Ordinal Decimus
The ordinal form decimus, -a, -um (tenth) is a regular first/second declension adjective. Unlike the cardinal decem, the ordinal declines fully: decimus vir (the tenth man), decimī virī (of the tenth man), decimō virō (to the tenth man), and so on. The derivative decimō, -āre (to select by lot every tenth person, to tithe) gives English “decimate,” though the modern English meaning has shifted to mean general destruction.
7. Decem in Partitive Expressions
In example 196.9, decem ex illīs (ten of those) shows decem used with the partitive construction ex + ablative. Latin can express partitive relationships in two ways: with the genitive (decem illōrum) or with ex/dē + ablative (decem ex illīs). Both are correct and common.
Common Mistakes to Avoid:
Students sometimes try to decline decem to match the noun it modifies — this is unnecessary. The word is invariable. Similarly, learners may forget that mīlia (thousands) is a noun requiring the genitive, while mīlle (thousand) is an adjective. Finally, the compound numerals 18 and 19 are formed by subtraction from twenty, not addition to ten — a frequent source of error.
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The number ten held profound significance in Roman civilization. The very structure of Roman society was organized on a decimal basis — from the earliest tribal divisions (cūriae of ten gentēs) to the military system where the basic cavalry unit was the decuria of ten horsemen.
The Decemvirī and Roman Law. In 451–450 BC, a commission of ten men — the decemvirī lēgibus scrībundīs — was appointed to codify Roman customary law. The result was the famous Twelve Tables (Duodecim Tabulae), the foundation of all subsequent Roman jurisprudence. This commission held supreme power in place of the consuls, and their work remained the basis of Roman legal education for centuries. Cicero reports that schoolboys of his generation still memorized the Twelve Tables as part of their education.
Decimātiō. The military punishment of decimation — executing every tenth soldier in a unit that had shown cowardice or mutiny — is one of the most notorious aspects of Roman discipline. The soldiers drew lots, and those selected were beaten to death by their own comrades. The practice was rare but attested from the Republic through the Empire. Crassus famously decimated units during the war against Spartacus in 71 BC.
The Roman Calendar. The original Roman calendar attributed to Romulus began in March (Mārtius), making December literally “the tenth month.” When January and February were later added to the beginning of the year, the numerical names September (7th), Octōber (8th), November (9th), and December (10th) became misaligned with their actual positions — a mismatch that persists in our modern calendar.
The Denārius. The silver coin called the denārius (from dēnī, “ten each”) was originally valued at ten assēs. Introduced around 211 BC, it became the standard silver denomination of the Roman Republic and Empire, and its name lives on in the currency names of many modern countries (the Arabic dīnār, the Macedonian denar).
Idiomatic Expressions:
Decemvirī — any board or commission of ten men, used in various official capacities throughout Roman history.
Decumānus (ager) — the main east-west road in a Roman camp or colonial town, related to the tenth cohort’s position.
Decuma — a tithe, one-tenth; the standard proportion of agricultural produce paid as tax in provincial administration, especially in Sicily under Roman rule, as described vividly by Cicero in his Verrīnae.
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Source: Caesar, Dē Bellō Gallicō I.7
Caesar describes the narrow passage near Geneva at the opening of the Gallic War, where the Helvetii sought to cross through Roman territory.
Part F-A: Interlinear Construed Text
Inter between montem the-mountain-ACC Iūram Jura-ACC et and flūmen the-river-ACC Rhodanum Rhône-ACC iter a-route-NOM erat there-was angustum narrow-NOM quod which-NOM nōn not amplius more-than decem ten pedēs feet-ACC in in lātitūdinem width-ACC patēbat lay-open
Part F-B: Natural Translation
Inter montem Iūram et flūmen Rhodanum iter erat angustum, quod nōn amplius decem pedēs in lātitūdinem patēbat. → “Between Mount Jura and the river Rhône there was a narrow passage, which extended no more than ten feet in width.”
Part F-C: Latin Text Only
Inter montem Iūram et flūmen Rhodanum iter erat angustum, quod nōn amplius decem pedēs in lātitūdinem patēbat.
Part F-D: Grammar Commentary
This passage, adapted from the opening of Caesar’s Dē Bellō Gallicō, demonstrates decem in a precise military-geographical description — exactly the kind of factual, measured prose for which Caesar is famous. The phrase nōn amplius decem pedēs (no more than ten feet) uses amplius as an adverb of comparison with the accusative of extent (pedēs in the accusative measuring spatial extent, parallel to the temporal accusative we saw in decem annōs). The relative clause quod...patēbat refers to iter (neuter nominative), with quod as the neuter nominative relative pronoun. The verb patēbat (from pateō, “lie open, extend”) is in the imperfect tense, describing the ongoing state of the terrain. The noun iter (neuter, third declension) means “route, passage, march” — one of the most common words in Caesar’s military vocabulary. The phrase in lātitūdinem with the accusative expresses the dimension being measured: “in width” or “in terms of breadth.”
Caesar’s use of precise numerical measurement is characteristic of his plain, factual style (genus tenue). He wants his reader — originally the Roman Senate and people — to understand the tactical reality: a gap only ten feet wide between mountain and river could be easily blocked.
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Part A: Interlinear Construed Text
This passage describes the creation and significance of Rome's first written legal code, the Twelve Tables (449 BCE).
Key Events: - 196.16-18: Ten men (decemvirs) were elected with supreme power - 196.19-20: They examined Greek laws and composed twelve tablets of Roman law - 196.21-23: These laws were publicly displayed and memorized by Roman boys, including young Cicero - 196.24-28: After ten months, the first decemvirs left office, but the second group refused to step down. Popular uprising ensued, and Appius Claudius was imprisoned. The republic was restored - 196.29-30: The Twelve Tables remained the foundation of Roman law for centuries; legal experts always returned to them as the source of law
Ablatives of Respect/Specification: - annō (196.16) - "in the year" (temporal ablative) - memoriā (196.22) - "by memory"
Accusative + Infinitive (Indirect Statement): - sē puerum...didicisse (196.23) - "that he as a boy learned" - sē...legere possent (196.21) - "that all citizens might be able to read"
Genitive of Material/Source: - fontem iūris (196.30) - "the source of law"
This passage illustrates Rome's transition from unwritten to written law and the enduring authority of the Twelve Tables. Part B: Natural Sentences
196.16 Annō trecentēsimō ab urbe conditā Rōmānī decem virōs ēlēgērunt. → “In the three-hundredth year from the founding of the city, the Romans chose ten men.”
196.17 Hī decem virī summam potestātem habēbant. → “These ten men held the highest power.”
196.18 Nūllī aliī magistrātūs eō annō creātī sunt. → “No other magistrates were elected that year.”
196.19 Decemvirī lēgēs Graecās studiōsē inspexērunt. → “The Board of Ten examined Greek laws diligently.”
196.20 Deinde duodecim tabulās lēgum Rōmānārum composuērunt. → “Then they composed twelve tablets of Roman laws.”
196.21 Hae tabulae in forō positae sunt ut omnēs cīvēs legere possent. → “These tablets were placed in the forum so that all citizens might read them.”
196.22 Puerī Rōmānī hās decem et duās tabulās memoriā tenēbant. → “Roman boys held these twelve tablets in memory.”
196.23 Cicerō ipse dīcit sē puerum hās lēgēs didicisse. → “Cicero himself says that as a boy he learned these laws.”
196.24 Post decem mēnsēs prīmī decemvirī magistrātū abīvērunt. → “After ten months, the first board of ten departed from office.”
196.25 Secundī tamen decemvirī potestātem dēpōnere nōluērunt. → “The second board of ten, however, refused to lay down their power.”
196.26 Populus Rōmānus contrā eōs surrēxit. → “The Roman people rose up against them.”
196.27 Appius Claudius, quī inter decem prīnceps erat, in carcerem ductus est. → “Appius Claudius, who was the chief among the ten, was led to prison.”
196.28 Ita rēs pūblica post decem virōrum dominātiōnem restitūta est. → “Thus the republic was restored after the tyranny of the ten men.”
196.29 Lēgēs tamen duodecim tabulārum per multa saecula mānsērunt. → “The laws of the Twelve Tables nevertheless endured through many centuries.”
196.30 Iūris cōnsultī Rōmānī semper ad hās decem et duās tabulās tamquam ad fontem iūris redībant. → “The Roman legal experts always returned to these twelve tablets as if to the source of law.”
Part C: Latin Text Only
196.16 Annō trecentēsimō ab urbe conditā Rōmānī decem virōs ēlēgērunt.
196.17 Hī decem virī summam potestātem habēbant.
196.18 Nūllī aliī magistrātūs eō annō creātī sunt.
196.19 Decemvirī lēgēs Graecās studiōsē inspexērunt.
196.20 Deinde duodecim tabulās lēgum Rōmānārum composuērunt.
196.21 Hae tabulae in forō positae sunt ut omnēs cīvēs legere possent.
196.22 Puerī Rōmānī hās decem et duās tabulās memoriā tenēbant.
196.23 Cicerō ipse dīcit sē puerum hās lēgēs didicisse.
196.24 Post decem mēnsēs prīmī decemvirī magistrātū abīvērunt.
196.25 Secundī tamen decemvirī potestātem dēpōnere nōluērunt.
196.26 Populus Rōmānus contrā eōs surrēxit.
196.27 Appius Claudius, quī inter decem prīnceps erat, in carcerem ductus est.
196.28 Ita rēs pūblica post decem virōrum dominātiōnem restitūta est.
196.29 Lēgēs tamen duodecim tabulārum per multa saecula mānsērunt.
196.30 Iūris cōnsultī Rōmānī semper ad hās decem et duās tabulās tamquam ad fontem iūris redībant.
Part D: Grammar Notes for Genre Section
This historical narrative illustrates several additional grammatical features alongside decem:
The Ablative Absolute. In 196.16, annō trecentēsimō ab urbe conditā contains the ablative absolute urbe conditā (”the city having been founded,” i.e., “from the founding of the city”). This is one of the most characteristic Latin constructions, where a noun and participle in the ablative stand grammatically independent from the main clause to express attendant circumstances.
Indirect Statement. In 196.23, Cicerō dīcit sē puerum hās lēgēs didicisse shows the accusative-infinitive construction for indirect speech. The subject of the infinitive (sē, reflexive = Cicero himself) is in the accusative; puerum is a predicative accusative (”as a boy”); didicisse is the perfect active infinitive of discō (learn). Literally: “Cicero says himself as-a-boy to-have-learned these laws.”
Purpose Clauses with ut. In 196.21, ut omnēs cīvēs legere possent (”so that all citizens might be able to read”) is a purpose clause with the imperfect subjunctive possent (from possum), following the secondary sequence after the main verb positae sunt.
The Ablative of Separation. In 196.24, magistrātū abīvērunt uses the ablative without a preposition to express separation: “they departed from office.” Verbs of separation, deprivation, and freeing commonly take the bare ablative in Latin.
The Compound Numeral duodecim. The narrative repeatedly uses duodecim (twelve), showing the compound formation: duo + decem → duodecim. Note that in 196.22 and 196.30 the phrase decem et duās tabulās is used as a periphrastic alternative, emphasizing the “ten plus two” composition.
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Classical Latin had a consistent relationship between spelling and pronunciation. The following notes apply to words appearing throughout this lesson:
The letter c is always pronounced [k] in Classical Latin, regardless of the following vowel. Thus decem = [ˈde.kem], Cicerō = [ˈki.ke.roː], carcerem = [ˈkar.ke.rem]. The Ecclesiastical pronunciation, which softens c before e and i to [tʃ], developed in the medieval period.
Long vowels are marked with macrons (ā, ē, ī, ō, ū) in pedagogical texts but were not written in antiquity. They are phonemically distinct: malus (bad) vs. mālus (apple tree), populus (people) vs. pōpulus (poplar). In this lesson: lēgēs (laws) has two long vowels; legiōnēs has a long ō and a long final ē.
The diphthong ae is pronounced [ae̯] in Classical Latin (similar to English “eye”), not [ɛː] as in later pronunciation. Thus tabulae = [ˈta.bʊ.lae̯].
Stress in Latin follows a simple rule: in words of two syllables, stress the first syllable; in words of three or more syllables, stress the penultimate syllable if it is heavy (contains a long vowel or ends in a consonant cluster), otherwise stress the antepenultimate. Thus: DE-cem, de-CEM-vi-rī, ma-gi-STRĀ-tūs.
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The Latinum Institute Classical Latin Reading Course teaches Latin through a frequency-based vocabulary approach combined with the time-tested construed reading method. Each lesson introduces one word from a systematically organized list of the 1,000 most useful Latin words, presented in context through authentic-style sentences and genuine literary citations.
The construed reading method — in which each Latin word is paired with its English gloss in the original word order — has been used for centuries to teach students how to read Latin naturally, without the artificial step of rearranging sentences into English syntax. By seeing the Latin word order preserved and each word independently glossed, the learner develops an intuitive sense of Latin sentence structure.
This is Lesson 196 of 1,000. The course progresses from the most common Latin words to increasingly specialized vocabulary, ensuring that students build a practical reading knowledge of the language. By the end of the course, students will have encountered the core vocabulary necessary to read Classical Latin authors with comprehension.
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