Genitive of Description (Quality): Latin Grammar

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GrammarGenitive of Description (Quality)

Genitive of Description (Quality)

A&G §345–345 N. 1|4 rules|0 practice questions

Latin can hang a description on a noun the way English uses an of-phrase: vir magnae virtūtis, "a man of great courage." The hard rule — the one A&G keeps repeating — is that the genitive of description never travels alone.

Vir virtūtis is ungrammatical; you must have an adjective doing real work (magnae, summae, tantae, ēius).

The other catch is that the ablative of description (vir magnā virtūte) covers almost the same ground.

In classical prose the two are nearly interchangeable, with a soft tilt: the genitive prefers essential qualities (the kind that define a person — character, dimensions, judgment), the ablative prefers incidental ones (the look of a body on a particular day).

When in doubt, ablative is the safer default; the genitive lives mostly in fixed shapes — ēius modī, measurements with pedum, and the big four adjectives māgnus / maximus / summus / tantus.

Learnings0 core · 1 AP claim

AP framework claims (1)— verbatim from AP CED

GRAM-1.EThe genitive case can be used to show descriptive properties of something (e.g., femina magnae sapientiae: a woman of great wisdom), show the whole of which a noun is a part (e.g., plus vini: more wine), or show a quasi-object of a noun implying action (e.g., cupiditas regni: desire for a kingdom).

Pattern

noun + adj. (gen.) + noun (gen.)

e.g. vir + magnae + virtūtis

Genitive of Description (Quality)

"a [head-noun] of [adj.] [quality]" — the genitive describes the head noun's character, size, or measure

The adjective is non-negotiable: vir virtūtis alone is ungrammatical. Common adjectives in prose: māgnus, maximus, summus, tantus, ēius / cūius modī.

Genitive-of-Description Phrases You'll Actually Meet

vir magnae virtūtis

vir magnae virtūtis = a man of great courage

critical

vir summae virtūtis

vir summae virtūtis = a man of the highest courage (A&G § 345)

critical

tantae virtūtis hominēs

tantae virtūtis hominēs = men of such great courage (B. G. ii. 27. 5)

critical

summae audāciae adulēscēns

summae audāciae adulēscēns = a young man of the highest daring (Sall. Cat. 18. 4)

common

tantae mōlis erat … — predicate use

tantae mōlis erat Rōmānam condere gentem = it was a task of such great effort to found the Roman race (Aen. i. 33)

common

māgnae est dēlīberātiōnis — predicate use

māgnae est dēlīberātiōnis = it is a matter of great deliberation (A&G § 345)

common

ēius modī / cūius modī — frozen

ēius modī tempestātēs = storms of that sort (B. G. iii. 29)

common

māgnī ponderis + noun

māgnī ponderis saxa = stones of great weight (B. G. ii. 29. 3)

common

numeral + pedum — measure

mūrus in altitūdinem pedum sēdecim = a wall sixteen feet high (B. G. i. 8. 1)

common

numeral + pedum — depth

fossa trium pedum = a trench three feet deep (A&G § 345. b)

common

See It In Action

ut non nequiquam tantae virtūtis hominēs iudicārī dēbēret ausōs esse trānsīre lātissimum flūmen

so that it had to be judged not in vain that men of such great courage had dared to cross so wide a river.

— B. G. ii. 27. 5

Tantae virtūtis is the textbook shape: an adjective in the genitive (tantae) plus an abstract noun in the genitive (virtūtis), latched onto hominēs. Drop tantae and the phrase collapses — that's the rule the spec keeps insisting on.

erat eōdem tempore Cn. Pīsō, adulēscēns nōbilis, summae audāciae, egēns, factiōsus

There was at the same time Cn. Piso, a young nobleman, of the highest audacity, penniless, factious.

— Sall. Cat. 18. 4

Sallust uses the genitive of description in a string of biographical labels for Piso — summae audāciae sits next to plain adjectives (egēns, factiōsus) as if it were one of them. That's the construction's natural home: characterizing a person.

Tantae mōlis erat Rōmānam condere gentem

Of such great effort was it to found the Roman race!

— Verg. Aen. i. 33

Vergil's famous line shows the predicate use: tantae mōlis (gen. of description) sits as a complement of erat, with the infinitive condere gentem as the real subject. The shape is still adj. + noun, both genitive — A&G § 345 covers this same pattern.

Genitive of Description vs. Ablative of Description

Same job, two cases. The choice is mostly stylistic — but the genitive needs an adjective and leans toward essential traits.

Genitive of Description

of [adj.] X — essential / defining

vir magnae virtūtis

a man of great virtue

Ablative of Description

with [adj.] X — incidental / observable

vir magnā virtūte

a man with great virtue

Tip: Ask: is the trait part of WHO the noun is (genitive default), or HOW it looks/feels right now (ablative default)? In classical prose the ablative is more common; the genitive clusters around māgnus / maximus / summus / tantus, ēius modī, and measurements.

Quick Check

Caesar writes tantae virtūtis hominēs (B. G. ii. 27. 5). What case is virtūtis, and why does it sit there?

Study Tips

•First reflex when you see a bare genitive describing a noun: check that an adjective is sitting next to it. No adjective → it isn't this construction; reread for possession or partitive.
•Memorize the four adjectives that license most genitives of quality in prose: māgnus, maximus, summus, tantus. Plus ēius / cūius modī and any number + pedum / passuum.
•Translate the phrase loosely as "of [great / such / the highest] X" or "a [adj.] X-ed one." English "of" is the workhorse, but "with" often reads better — that's the ablative talking through your translation.

Learnings0 core · 1 AP claim

AP framework claims (1)— verbatim from AP CED

See It In Action

ut non nequiquam tantae virtūtis hominēs iudicārī dēbēret ausōs esse trānsīre lātissimum flūmen

so that it had to be judged not in vain that men of such great courage had dared to cross so wide a river.

— B. G. ii. 27. 5

erat eōdem tempore Cn. Pīsō, adulēscēns nōbilis, summae audāciae, egēns, factiōsus

There was at the same time Cn. Piso, a young nobleman, of the highest audacity, penniless, factious.

— Sall. Cat. 18. 4

Tantae mōlis erat Rōmānam condere gentem

Of such great effort was it to found the Roman race!

— Verg. Aen. i. 33

Study Tips

•First reflex when you see a bare genitive describing a noun: check that an adjective is sitting next to it. No adjective → it isn't this construction; reread for possession or partitive.

•Memorize the four adjectives that license most genitives of quality in prose: māgnus, maximus, summus, tantus. Plus ēius / cūius modī and any number + pedum / passuum.

•Translate the phrase loosely as "of [great / such / the highest] X" or "a [adj.] X-ed one." English "of" is the workhorse, but "with" often reads better — that's the ablative talking through your translation.