Latin numerals

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The Latin numerals are the words used to denote numbers within the Latin language. They are essentially based on their Proto-Indo-European ancestors, and the Latin cardinal numbers are largely sustained in the Romance languages. In Antiquity and during the Middle Ages they were usually represented by Roman numerals in writing.

Latin numeral roots are used frequently in modern English, particularly in the names of large numbers.


The Latin language had several sets of number words used for various purposes. Some of those sets are shown in the tables below.

Cardinal numerals[edit]

The cardinal numerals are the ordinary numbers used for counting ordinary nouns ('one', 'two', 'three' and so on):

1 I ūnus, ūna, ūnum 11 XI ūndecim 21 XXI vīgintī et ūnus 101 CI centum et ūnus
2 II duo, duae, duo 12 XII duodecim 22 XXII vīgintī et duo 200 CC ducentī, ducentae, ducenta
3 III trēs, tria 13 XIII tredecim 30 XXX trīgintā 300 CCC trecentī, trecentae, trecenta
4 IV quattuor 14 XIV quattuordecim 40 XL quadrāgintā 400 CD quadringentī, quadringentae, quadringenta
5 V quīnque 15 XV quīndecim 50 L quīnquāgintā 500 D quīngentī, quīngentae, quīngenta
6 VI sex 16 XVI sēdecim 60 LX sexāgintā 600 DC sescentī, sescentae, sescenta
7 VII septem 17 XVII septendecim 70 LXX septuāgintā 700 DCC septingentī, septingentae, septingenta
8 VIII octō 18 XVIII duodēvīgintī 80 LXXX octōgintā 800 DCCC octingentī, octingentae, octingenta
9 IX novem 19 XIX ūndēvīgintī 90 XC nōnāgintā 900 Cↀ nōngentī, nōngentae, nōngenta
10 X decem 20 XX vīgintī 100 C centum 1000 mīlle

The conjunction et between numerals can be omitted: vīgintī ūnus, centum ūnus. Et is not used when there are more than two words in a compound numeral: centum trīgintā quattuor. The word order in the numerals from 21 to 99 may be inverted: ūnus et vīgintī. Numbers ending in 8 or 9 are usually named in subtractive manner: duodētrīgintā, ūndēquadrāgintā. Numbers may either precede or follow their noun (see Latin word order).

Most numbers are invariable and do not change their endings:

  • regnāvit Ancus annōs quattuor et vīgintī (Livy)[1]
'Ancus reigned for 24 years'

However, the numbers 1, 2, 3, and 200, 300, etc. change their endings for gender and grammatical case. Ūnus 'one' declines like a pronoun and has genitive ūnīus (or ūnius) and dative ūnī:

The first three numbers have masculine, feminine and neuter forms fully declined as follows (click on GL or Wh to change the table to the American order as found in Gildersleeve and Lodge, or Wheelock):

Declension 1 m f n 2 m f n 3 mf n Br GL Wh
Nominative ūnus ūna ūnum duo duae duo trēs tria 1 1 1
Vocative ūne ūna ūnum duo duae duo trēs tria 2 5 6
Accusative ūnum ūnam ūnum duōs/duo duās duo trēs/trīs tria 3 4 4
Genitive ūnīus/-ius ūnīus ūnīus duōrum duārum duōrum trium trium 4 2 2
Dative ūnī ūnī ūnī duōbus duābus duōbus tribus tribus 5 3 3
Ablative ūnō ūnā ūnō duōbus duābus duōbus tribus tribus 6 6 5
  • omnēs ūnius aestimēmus assis (Catullus)
'let us value them (at the value) of a single as!'
  • duo ex tribus fīliīs (Curtius)
'two of his three sons'
  • dīvidunt tōtam rem in duās partīs (Cicero)
'they divide the whole thing into two parts'

Mīlle '1000' is indeclinable in the singular but variable in the plural:

  • dā mī bāsia mīlle, deinde centum (Catullus)
'give me a thousand kisses, then a hundred'
  • mīllia aliquantō plūra quam trecenta (Augustus)
'slightly more than 300,000'

When it is plural, the noun it refers to is put in the genitive case:

  • cum sex mīlibus equitum (Curtius)
'accompanied by six thousand(s) (of) cavalrymen'

Mīlle passūs '1000 paces' (plural mīlia passuum) is the Latin for a mile:

  • quīcumque tē angariāverit mīlle passūs, vade cum illō et alia duo (Vulgate Bible)
'whoever compels you to walk a mile, go with him another two'

When the number is plural, the genitive passuum is sometimes omitted:

  • non longius ab oppidō X mīlibus (Caesar)
'not further than 10 miles from the town'

Ordinal numerals[edit]

Ordinal numerals all decline like normal first- and second-declension adjectives. When declining two-word ordinals (thirteenth onwards), both words decline to match in gender, number and case.

Note: secundus only means 'second' in the sense of 'following'. The adjective alter, altera, alterum meaning 'other [of two]' was more frequently used in many instances where English would use 'second'.

Ordinal numbers, not cardinal numbers, are commonly used to represent dates, because they are in the format of 'in the tenth year of Caesar', etc. which also carried over into the anno Domini system and Christian dating, e.g. annō post Chrīstum nātum centēsimō for AD 100.

1 I prīmus 11 XI ūndecimus 21 XXI vīcēsimus prīmus 101 CI centēsimus prīmus
2 II secundus 12 XII duodecimus 22 XXII vīcēsimus secundus 200 CC ducentēsimus
3 III tertius 13 XIII tertius decimus 30 XXX trīcēsimus 300 CCC trecentēsimus
4 IV quārtus 14 XIV quārtus decimus 40 XL quadrāgēsimus 400 CD quadringentēsimus
5 V quīntus 15 XV quīntus decimus 50 L quīnquāgēsimus 500 D quīngentēsimus
6 VI sextus 16 XVI sextus decimus 60 LX sexāgēsimus 600 DC sescentēsimus
7 VII septimus 17 XVII septimus decimus 70 LXX septuāgēsimus 700 DCC septingentēsimus
8 VIII octāvus 18 XVIII duodēvīcēsimus 80 LXXX octōgēsimus 800 DCCC octingentēsimus
9 IX nōnus 19 XIX ūndēvīcēsimus 90 XC nōnāgēsimus 900 Cↀ nōngentēsimus
10 X decimus 20 XX vīcēsimus 100 C centēsimus 1000 mīllēsimus
  • diē septimō pervēnit (Caesar)[2]
'he arrived on the seventh day'

Ordinal numerals + -ārius[edit]

Based on the ordinary ordinals is another series of adjectives: prīmārius 'of the first rank', secundārius 'of the second class, of inferior quality', tertiārius 'containing a third part', quārtārius 'a quarter, fourth part', quīntārius 'containing five parts', 'five-sixths', sextārius 'a one-sixth part of a congius, 'pint', and so on.[3]

  • domī suae vir prīmārius (Cicero)
'the leading man of his family'
  • secundāriī pānis quīnās sēlībrās (Pliny the Elder)
'five half-pounds of second-class bread'
  • tertiārum (stannum) (Pliny the Elder)
'lead alloy containing one-third white metal'
  • quārtāriōs vīnī (Livy)
'quarter-pints of wine'
'five-sixths' (taking a sextārius as the whole)
  • oleī sextārius (Celsus)
'a pint of oil'
  • octāvārium vectīgal (Justinian)
'an eighth-part tax'

Plūrāle tantum numerals[edit]

Certain nouns in Latin were plurālia tantum, i.e. nouns that were plural but which had a singular meaning, for example litterae 'a letter', castra 'a camp', catēnae 'a set of chains', vestīmenta '(a set of) clothes', hibernae 'winter quarters', nūptiae 'wedding', quadrīgae 'quadriga' etc. A special series of numeral adjectives was used for counting these, namely ūnī, bīnī, trīnī, quadrīnī, quīnī, sēnī, and so on. Thus Roman authors would write: ūnae litterae 'one letter', trīnae litterae 'three letters', quīna castra 'five camps', etc.

Except for the numbers 1, 3, and 4 and their compounds, the plurale tantum numerals are identical with the distributive numerals (see below).

1 I ūnī 11 XI ūndēnī 21 XXI vīcēnī ūnī 101 CI centēnī singulī
2 II bīnī 12 XII duodēnī 22 XXII vīcēnī bīnī 200 CC ducēnī
3 III trīnī 13 XIII trinī dēnī 30 XXX trīcēnī 300 CCC trecēnī
4 IV quadrīnī 14 XIV quadrīnī dēnī 40 XL quādrāgēnī 400 CD quadringēnī
5 V quīnī 15 XV quīnī dēnī 50 L quīnquāgēnī 500 D quīngēnī
6 VI sēnī 16 XVI sēnī dēnī 60 LX sexāgēnī 600 DC sescēnī
7 VII septēnī 17 XVII septēnī dēnī 70 LXX septuāgēnī 700 DCC septingēnī
8 VIII octōnī 18 XVIII duodēvīcēnī 80 LXXX octōgēnī 800 DCCC octingēnī
9 IX novēnī 19 XIX ūndēvīcēnī 90 XC nōnāgēnī 900 Cↀ nōngēnī
10 X dēnī 20 XX vīcēnī 100 C centēnī 1000 mīllēnī
  • non dīcimus bīga ūna, quadrīgae duae, nūptiae trēs, sed prō eō ūnae bīgae, bīnae quadrīgae, trīnae nūptiae (Varro)
'We don't say una biga (one two-horse chariot), duae quadrigae (two four-horse chariots), tres nuptiae (three weddings) but instead unae bigae, binae quadrigae, trinae nuptiae'.
  • Tullia mea vēnit ad mē ... litterāsque reddidit trīnās (Cicero)[4]
'My daughter Tullia came to me ... and delivered (no fewer than) three letters'
  • Octāvius quīnīs castrīs oppidum circumdedit (Caesar)[5]
'Octavius surrounded the town with five camps'

Distributive numerals[edit]

Another set of numeral adjectives, similar to the above but differing in the adjectives for 1, 3, and 4, were the distributive numerals: singulī, bīnī, ternī, quaternī, quīnī, sēnī, and so on. The meaning of these is 'one each', 'two each' (or 'in pairs') and so on, for example

'there he began erecting towers with three storeys each'
  • bīnī senātōrēs singulīs cohortibus praepositī (Livy)
'a pair of senators was put in charge of each group of soldiers'.
  • lēgātī ternī in Āfricam ... et in Numidiam missī (Livy)[6]
'three ambassadors were sent to Africa, and three to Numidia'
  • in singulōs equitēs ... nummōs quīnōs vīcēnōs dedērunt (Livy)[7]
'for each individual cavalryman they gave 25 coins'

The word singulī is always plural in this sense in the classical period.[8]

The distributive numerals are also used for multiplying:[9]

'three threes, which are nine'

In numbers 13 to 19, the order may be inverted, e.g. dēnī ternī instead of ternī dēnī.[10]

1 I singulī 11 XI ūndēnī 21 XXI vīcēnī singulī 101 CI centēnī singulī
2 II bīnī 12 XII duodēnī 22 XXII vīcēnī bīnī 200 CC ducēnī
3 III ternī 13 XIII ternī dēnī 30 XXX trīcēnī 300 CCC trecēnī
4 IV quaternī 14 XIV quaternī dēnī 40 XL quādrāgēnī 400 CD quadringēnī
5 V quīnī 15 XV quīnī dēnī 50 L quīnquāgēnī 500 D quīngēnī
6 VI sēnī 16 XVI sēnī dēnī 60 LX sexāgēnī 600 DC sescēnī
7 VII septēnī 17 XVII septēnī dēnī 70 LXX septuāgēnī 700 DCC septingēnī
8 VIII octōnī 18 XVIII duodēvīcēnī 80 LXXX octōgēnī 800 DCCC octingēnī
9 IX novēnī 19 XIX ūndēvīcēnī 90 XC nōnāgēnī 900 Cↀ nōngēnī
10 X dēnī 20 XX vīcēnī 100 C centēnī 1000 mīllēnī

Distributive numerals + -ārius[edit]

Based on the distributive numerals are derived a series of adjectives ending in -ārius: singulārius 'unique', 'extraordinary', 'of one part', 'singular', bīnārius 'of two parts', ternārius 'of three parts', quaternārius 'of four parts', and so on.

1 I singulārius 11 XI ūndēnārius 21 XXI ? 101 CI ?
2 II bīnārius 12 XII duodēnārius 22 XXII ? 200 CC ducēnārius
3 III ternārius 13 XIII tredēnārius 30 XXX trīcēnārius 300 CCC trecēnārius
4 IV quaternārius 14 XIV quattuordēnārius 40 XL quadrāgēnārius 400 CD quadringēnārius
5 V quīnārius 15 XV quīndēnārius 50 L quīnquāgēnārius 500 D quīngēnārius
6 VI sēnārius 16 XVI sēdēnārius 60 LX sexāgēnārius 600 DC sescēnārius
7 VII septēnārius 17 XVII septendēnārius 70 LXX septuāgēnārius 700 DCC septingēnārius
8 VIII octōnārius 18 XVIII duodēvīcēnārius 80 LXXX octōgēnārius 800 DCCC octingēnārius
9 IX novēnārius 19 XIX ūndēvīcēnārius 90 XC nōnāgēnārius 900 Cↀ nōngēnārius
10 X dēnārius 20 XX vīcēnārius 100 C centēnārius 1000 mīllēnārius

Often these adjectives specify the size or weight of something. The usual meaning is 'of so many units', the units being feet, inches, men, pounds, coins, or years, according to context:

  • scrobēs quaternāriī, hoc est quōquōversus pedum quattuor (Columella)
'four-foot ditches, that is, four foot long in every direction'
  • quīnāria (fistula), dicta ā diametrō quīnque quadrantum (Frontinus)
'a five-digit pipe, named from its diameter of five digits'
  • quīngēnāriae cohortēs (Curtius)
'five-hundred men battalions'
  • quīngēnārius thōrāx (Pliny the Elder)
'a five-hundred pound suit of body armour'
  • quīngēnāria poena (Gaius)
'a five-hundred as penalty' (an as was a bronze coin)

They can also be used for specifying age:

  • exhērēdāta ab octōgēnāriō patre (Pliny the Younger)[11]
'disinherited by her 80-year-old father'

Some of these words have a specialised meaning. The sēnārius was a kind of metre consisting of six iambic feet commonly used in spoken dialogue in Roman comedy. There were also metres called the septēnārius and octōnārius (see Metres of Roman comedy).

The dēnārius was a silver coin originally worth ten assēs (but later sixteen assēs); but there was also a gold dēnārius, mentioned by Pliny the Elder and Petronius, worth 25 silver dēnāriī. The silver dēnārius is often mentioned in the New Testament, and was stated to be the day's pay in the parable of the Labourers in the Vineyard.[12]

Adverbial numerals[edit]

Adverbial numerals are (as the name states) indeclinable adverbs, but because all of the other numeral constructions are adjectives, they are listed here with them. Adverbial numerals give how many times a thing happened. semel 'once', bis 'twice', ter 'thrice, three times', quater 'four times', and so on.

1 I semel 11 XI ūndeciēns 21 XXI vīciēns semel 101 CI centiēns semel
2 II bis 12 XII duodeciēns 22 XXII vīciēns bis 200 CC ducentiēns
3 III ter 13 XIII trēdeciēns 30 XXX trīciēns 300 CCC trecentiēns
4 IV quater 14 XIV quattuordeciēns 40 XL quadrāgiēns 400 CD quadringentiēns
5 V quinquiēns 15 XV quīndeciēns 50 L quīnquāgiēns 500 D quīngentiēns
6 VI sexiēns 16 XVI sēdeciēns 60 LX sexāgiēns 600 DC sescentiēns
7 VII septiēns 17 XVII septendeciēns 70 LXX septuāgiēns 700 DCC septingentiēns
8 VIII octiēns 18 XVIII duodēvīciēns 80 LXXX octōgiēns 800 DCCC octingentiēns
9 IX noviēns 19 XIX ūndēvīciēns 90 XC nōnāgiēns 900 Cↀ nōngentiēns
10 X deciēns 20 XX vīciēns 100 C centiēns 1000 mīlliēns

The suffix -iēns may also be spelled -iēs: quinquiēs, sexiēs, etc.

  • equidem deciēs dīxī (Plautus)[13]
'indeed I've said it ten times already'

Multiplicative numerals[edit]

Multiplicative numerals are declinable adjectives. simplex 'single', duplex 'double', triplex 'treble', quadruplex 'fourfold', and so on.

1 I simplex 11 XI ūndecuplex 21 XXI vīgentuplex simplex 101 CI centuplex simplex
2 II duplex 12 XII duodecuplex 22 XXII vīgentuplex duplex 200 CC ducentuplex
3 III triplex 13 XIII trēdecuplex 30 XXX trīgintuplex 300 CCC trecentuplex
4 IV quadruplex 14 XIV quattuordecuplex 40 XL quadrāgintuplex 400 CD quadringentuplex
5 V quīncuplex 15 XV quīndecuplex 50 L quīnquāgintuplex 500 D quīngentuplex
6 VI sextuplex 16 XVI sēdecuplex 60 LX sexāgintuplex 600 DC sescentuplex
7 VII septuplex 17 XVII septendecuplex 70 LXX septuāgintuplex 700 DCC septingentuplex
8 VIII octuplex 18 XVIII duodēvīgentuplex 80 LXXX octōgintuplex 800 DCCC octingentuplex
9 IX nōnuplex 19 XIX ūndēvīgentuplex 90 XC nōnāgintuplex 900 Cↀ nōngentuplex
10 X decuplex 20 XX vīgentuplex 100 C centuplex 1000 mīlliplex

These numerals decline as 3rd declension adjectives:

  • [Caesar] triplicem aciem instruxit (Caesar)
'(Caesar) arranged his soldiers in a triple line'
  • tabellās duplicēs tenentem (Suetonius)
'holding a pair of writing tablets consisting of two leaves'

For completeness all the numbers have been given above. Not all of these numerals are attested in ancient books, however.

Based on this series of numerals there is a series of adverbs: simpliciter 'simply, frankly', dupliciter 'doubly, ambiguously', tripliciter 'in three different ways' etc., as well as verbs such as duplicāre 'to double', triplicāre 'to triple', quadruplicāre 'to make four times as much', and so on.[8]

Proportional numerals[edit]

Proportional numerals are declinable adjectives. simplus 'simple', duplus 'twice as great', triplus 'thrice as great', quadruplus 'four times as great', and so on.

1 I simplus 11 XI ūndecuplus 21 XXI vīgentuplus simplus 101 CI centuplus simplus
2 II duplus 12 XII duodecuplus 22 XXII vīgentuplus duplus 200 CC ducentuplus
3 III triplus 13 XIII trēdecuplus 30 XXX trīgintuplus 300 CCC trecentuplus
4 IV quadruplus 14 XIV quattuordecuplus 40 XL quadrāgintuplus 400 CD quadringentuplus
5 V quīncuplus 15 XV quīndecuplus 50 L quīnquāgintuplus 500 D quīngentuplus
6 VI sextuplus 16 XVI sēdecuplus 60 LX sexāgintuplus 600 DC sescentuplus
7 VII septuplus 17 XVII septendecuplus 70 LXX septuāgintuplus 700 DCC septingentuplus
8 VIII octuplus 18 XVIII duodēvīgentuplus 80 LXXX octōgintuplus 800 DCCC octingentuplus
9 IX nōnuplus 19 XIX ūndēvīgentuplus 90 XC nōnāgintuplus 900 Cↀ nōngentuplus
10 X decuplus 20 XX vīgentuplus 100 C centuplus 1000 mīlliplus

These are often used as nouns: simplum 'the simple sum', duplum 'double the amount of money' and so on.[8]

  • duplam pecūniam in thēsaurōs repōnī (Livy)[14]
'double the amount of money to be replaced in the treasuries'

Linguistic details[edit]

Cardinal numbers[edit]


The numeral ūnus < Old Latin oinos ‘one’, with its cognates Old Irish óen ‘one’, Gothic ains ‘one’, Ancient Greek οἴνη oínēace on dice’, and the first part of Old Church Slavonic inorogŭ ‘Unicorn’, harks back to Proto-Indo-European *Hoi̯-no-s. The genitive forms ūnīus, ūnĭus and the dative form ūnī match the pronominal declension (cf. hujus, illius etc.), the remaining forms (including a rare gen. f. ūnae) conform with those of first and second declension adjectives.[15][16] Nominative and accusative forms persist within the Romance languages as numeral and also in its secondarily acquired role as indefinite article, e. g. Old French and Occitan uns, une, un, Italian un, una, Spanish un, una, Portuguese um, uma, Romanian un, o.[17]


The masculine nominative/accusative forms dŭŏ < Old Latin dŭō ‘two’ is a cognate to Old Welsh dou ‘two’,[16] Greek δύω dýō ‘two’, Sanskrit दुवा duvā ‘two’, Old Church Slavonic dŭva ‘two’, that imply Proto-Indo-European *duu̯o-h1, a Lindeman variant of monosyllabic *du̯o-h1, living on in Sanskrit द्वा dvā ‘two’, and slightly altered in Gothic twai ‘two’, German zwei ‘two’ etc.; the feminine dŭae points to an ancestral form *duu̯ah2-ih1. Both forms bear a dual ending, which otherwise in Latin is preserved only in ambō ‘both’, and possibly in octō ‘eight’. The accusative forms dŭōs m., dŭās f., the genitive dŭom, classical dŭōrum m./n., dŭārum f., and the dative/ablative dŭōbus m./n., dŭābus f., are original Latin formations replicating nominal declension patterns; at times, duo stands in for other case forms, especially when combined with invariant numerals, e. g. duo et vīgintī ‘twenty-two’, duodētrīgintā ‘twenty-eight’.[15][18]

Most Romance languages sustain an invariant form developed from the masculine accusative duōs > Spanish, Catalan, Occitan dos, French deux, Romansh duos, dus; Italian due seems to preserve the feminine nominative duae (or may have evolved from the feminine accusative duas).[17] Portuguese inflects masculine dois and feminine duas; Romanian has doi and două, respectively.

trēs, tria[edit]

The masculine and feminine nominative form trēs ‘three’ and its cognates Gothic þreis ‘three’, Greek τρεῖς treîs ‘three’, Sanskrit त्रयः trayaḥ ‘three’ are based on Proto-Indo-European *trei̯-es; the original accusative form trīs, matching Umbrian trif, Gothic þrins, Old Irish trí,[16] Greek τρίνς tríns < Proto-Indo-European *tri-ns, was being superseded from preclassical Latin onward. The neuter tria corresponds to Umbrian triia and Greek τρία tría. The genitive trium is a direct descendant of Proto-Indo-European *trii̯-om, unlike e. g. Greek τριῶν triôn with long -ōn < -o-om, taken from the second declension; the dative/ablative form tribus, as well as Umbrian tris < *trifos, sustains Proto-Indo-European *tri-bʰos.[15][18] The Romance languages only preserve one invariant form reflecting Latin trēs > Spanish, Catalan, Occitan tres, Portuguese três, French trois, Romansh trais, treis, Romanian trei.[17]


The invariant numeral quattuor ‘four’ does not fully correspond to any of its cognates in other languages, as Oscan petora ‘four’, Greek τέσσαρες téssares ‘four’, Old Irish cethair ‘four’, Gothic fidwôr ‘four’, Lithuanian keturì ‘four’, Old Church Slavonic četyre ‘four’ point to a Proto-Indo-European base *kʷetu̯or-, that should appear as *quetuor in Latin; the actual -a- has been explained as epenthetic vowel emerging from a zero-grade *kʷtu̯or-. The geminate -tt- might have been established to compensate the fluctuating quality of succeeding -u- between non-syllabic glide and full vowel apparent since Old Latin; in the postclassical form quattor this sound is dropped altogether, and in most Romance languages the second syllable is subject to syncope, which then is compensated by an additional vowel at the very end of the word, as in Spanish cuatro, Portuguese quatro, Italian quattro, French, Occitan, Catalan quatre, Romanian patru.[15][18][17]


The cardinal number quīnque ‘five’, with its cognates Old Irish coíc ‘five’, Greek πέντε pénte ‘five’, Sanskrit पञ्च pañca ‘five’, leads back to Proto-Indo-European pénkʷe; the long -ī-, confirmed by preserved -i- in most Romance descendants, must have been transferred from the ordinal quīntus ‘fifth’, where the original short vowel had been regularly lengthened preceding a cluster with a vanishing fricative: quīntus < *quiŋxtos < *kʷuiŋkʷtos < *kʷeŋkʷ-to-s. The assimilation of antevocalic *p- to -kʷ- of the following syllable is a common feature of the Italic languages as well as the Celtic languages.[15][18]

See also[edit]


  1. ^ Livy, 1.35.1.
  2. ^ Caesar, 1.10.4
  3. ^ Definitions from Lewis and Short A Latin Dictionary.
  4. ^ Cicero, Att. 11.17
  5. ^ Caesar, B.C. 3.9
  6. ^ Livy, 36.3
  7. ^ Livy, 22.54
  8. ^ a b c Lewis & Short, Latin Dictionary.
  9. ^ Allen & Greenough (1903), New Latin Grammar, §137.
  10. ^ C. G. Zumpt, "A Grammar of the Latin Language", 4th edition, 1836, translated by John Kenrick, p. 73
  11. ^ Pliny, Letters, 6.33.2.
  12. ^ e.g. Matt. 20' cf. Matt. 22.
  13. ^ Plautus, Amphitruo 575
  14. ^ Livy, 29.19.
  15. ^ a b c d e Manu Leumann, Lateinische Laut- und Formenlehre, Reprint of the 5th ed. from 1926–1928, München 1977, §§ 163b/376/378.
  16. ^ a b c Alexander Falileyev, Etymological Glossary of Old Welsh, Tübingen 2000, pp. 49/150/154.
  17. ^ a b c d Paul Georg Band, Zahlwörter im Sprachenvergleich. Ein Streifzug in die Geschichte der indogermanischen Sprachen an Hand ihrer Zahlwörter, Wien 1998, p. 12 f.
  18. ^ a b c d Gerhard Meiser, Historische Laut- und Formenlehre der lateinischen Sprache, Darmstadt 1998, §§ 72.2/88/116.