The case of a noun determines what it is doing in the sentence and is essentially different forms of the word. Cases are fundamental to Latin grammar, because of the lack of an article. To an extent, we have them in English. Let’s look at an English example.
We use these different forms of these words depending on what the noun is doing in the sentence. We would say, ‘I gave it to him’, but ‘He gave it to me’.
The definitions of the cases are:
NOMINATIVE – The subject of the sentence, the noun that is ‘doing’ something in the sentence. In ‘The apple fell from the tree’, the apple is the subject and therefore is nominative. In English it is generally the noun that comes before the verb.
VOCATIVE – This case is used to address a person or thing by name or title. It can be singular or plural, e.g. ‘Come here, boy!’ or ‘Ladies and gentlemen.’
ACCUSATIVE – The object of the sentence, or the thing that something is being ‘done’ to. In ‘The dog bit the man’, the man is the one being bitten and so is accusative (the dog is nominative). It is also used after certain prepositions. In English it is generally the noun that comes after the verb.
GENITIVE – The possessive case: of ____, ___’s or ___s’. For example: Peter’s, of the church, the boys’. The apostrophe or possessiveness would be represented by the genitive case; ‘Peter’, ‘church’ and ‘boys’ would all be nouns in the genitive case.
DATIVE – Represents action forward (dative means ‘giving’): more simply, to ___ or for ___. For example, ‘I gave the money to my mother’. I am nominative, the money is accusative and my mother is dative as she is the one receiving the money.
Beware the concealed dative! If you say, ‘I gave him a present’, the noun that comes after the verb is ‘him’, but he isn’t really thing you’re giving, so it isn’t accusative. The accusative is ‘present’ and ‘him’ is dative. This especially applies to the verbs ‘give’ and ‘tell’ in English.
ABLATIVE – Represents action away (ablative means ‘taking away’): more simply, by ___ or from ___. For example, ‘I received a present from him’ – him is ablative. The ablative also follows certain prepositions.
Note! If you say ‘by or from’ followed by a noun, and that noun is a person, there must be a preposition as well. If that noun is an inanimate object, no preposition is needed. Examples:
I killed him with a sword – sword is ablative, no preposition needed. VS. I went to town with my friends – friends is ablative but preposition ‘with’ is required.
He was crushed by an avalanche – avalanche is ablative, no preposition needed. VS. Antony was beaten by Octavius – Octavius is ablative but preposition ‘by’ is required.
LOCATIVE – The locative case is used for names of cities, small islands and some nouns. It is used when saying, ‘in Rome’ or ‘at home’. It is used INSTEAD OF THE PREPOSITION ‘IN/AT’.
The locative case is not an independent case because it simply looks like one of the other cases, depending on the declension and number of the noun. The rules are as follows:
For first and second declension singular nouns, the locative case looks like the genitive
For first and second declension plural nouns, the locative case looks like the dative
For third declension singular and plural nouns, the locative case looks like the ablative
For fourth declension singular nouns, the locative has a separate ending, which is –i (domi, humi).
The nouns that use the locative case are:
domus (home), rus (countryside), humus (ground), focus (hearth), militia (military service).
The names of islands that do NOT take the locative are:
Sicily, Sardinia, Corsica, Crete, Cyprus
It is vital to understand cases of nouns (as well as the translation of verb tenses) in order to progress in Latin. Some people may be taught to ‘pick up’ the cases as they go along, which is fine when translating ‘Caecilius est in horto’, but when it comes to translating the Aeneid, for example, it is impossible to do it without knowing the cases.