Latin Reference — Vol. I: The Case System
The six cases
| Case | Function | English signal | Example |
|---|---|---|---|
| Nominative | Subject; the doer | plain noun before the verb | puella videt — the girl sees |
| Genitive | Possession, "of"-relation | of X / X's | liber puellae — the girl's book |
| Dative | Indirect object; recipient or beneficiary | to/for X | puellae librum dat — he gives a book to the girl |
| Accusative | Direct object; also goal of motion | noun after the verb; to(wards) with motion | puellam videt — he sees the girl |
| Ablative | Means, manner, accompaniment, source, location | by / with / from / in X | cum puellā — with the girl |
| Vocative | Direct address | O X! | puella! — girl! |
Pithy anchors: genitive = of/'s · dative = to/for · ablative = by/with/from/in. Lock those in and half the battle is won.
Prepositions and the cases they trigger
Latin prepositions are locked to specific cases — spotting the preposition tells you the case of the next noun.
Accusative triggers (broadly: motion toward, through, against)
| Prep | Meaning |
|---|---|
| ad | to, towards |
| per | through |
| ante | before, in front of |
| post | after, behind |
| inter | between, among |
| trans | across |
| circum | around |
| contrā | against |
Ablative triggers (broadly: source, separation, accompaniment)
| Prep | Meaning |
|---|---|
| ā / ab | from, away from |
| ē / ex | out of |
| cum | with |
| dē | down from; concerning |
| sine | without |
| prō | on behalf of, in front of |
The in/sub rule: in and sub take accusative for motion (in urbem — into the city) and ablative for location (in urbe — in the city). It looks irregular but is the most logical thing in the language: accusative marks goals; ablative marks where you already are.
Why ad (acc) but ab (abl) when both involve motion? Accusative marks goals and targets; ablative marks sources and separation. Ablative itself derives from ab + lātum, "carried away from".
Declension endings
First declension (f.) — puella
| Case | Sing. | Pl. |
|---|---|---|
| Nom | -a | -ae |
| Gen | -ae | -ārum |
| Dat | -ae | -īs |
| Acc | -am | -ās |
| Abl | -ā | -īs |
| Voc | -a | -ae |
Second declension (m.) — amīcus
| Case | Sing. | Pl. |
|---|---|---|
| Nom | -us | -ī |
| Gen | -ī | -ōrum |
| Dat | -ō | -īs |
| Acc | -um | -ōs |
| Abl | -ō | -īs |
| Voc | -e | -ī |
Second declension (n.) — templum
| Case | Sing. | Pl. |
|---|---|---|
| Nom | -um | -a |
| Gen | -ī | -ōrum |
| Dat | -ō | -īs |
| Acc | -um | -a |
| Abl | -ō | -īs |
Neuter rule: nominative and accusative are always identical, and the plural of both is always -a.
Third declension (m./f.) — mīles, mīlitis
| Case | Sing. | Pl. |
|---|---|---|
| Nom | (varies) | -ēs |
| Gen | -is | -um |
| Dat | -ī | -ibus |
| Acc | -em | -ēs |
| Abl | -e | -ibus |
Third declension nominatives are irregular; the genitive singular reveals the stem (mīles → mīlit-). Dictionaries list both for this reason.
One noun, all cases — puella
| Case | Form | Sentence | Translation |
|---|---|---|---|
| Nom | puella | Puella in hortō ambulat. | The girl walks in the garden. |
| Gen | puellae | Liber puellae in mēnsā est. | The girl's book is on the table. |
| Dat | puellae | Māter puellae dōnum dat. | The mother gives a gift to the girl. |
| Acc | puellam | Mīles puellam videt. | The soldier sees the girl. |
| Abl | puellā | Cum puellā ad templum ambulāmus. | We walk to the temple with the girl. |
| Voc | puella | Puella, venī hūc! | Girl, come here! |
| Acc (motion) | puellam | Ad puellam currit. | He runs towards the girl. |
This is the table to drill: reading one noun shift through seven contexts is what makes the pattern click.