Vitulus ad arborem ligatur, sub cuius umbra meridie manet.

Because vitulus is the subject of the sentence.

• vitulus = the calf
• In Latin, the subject of a finite verb is normally in the nominative.
• Here, the verbs are ligatur and manet, and the calf is the one being tied and the one remaining.

So vitulus is nominative singular.

Ligatur means is tied or is being tied, not ties.

It is passive because the calf is receiving the action, not doing it.

• ligat = he/she/it ties
• ligatur = he/she/it is tied

So Vitulus ad arborem ligatur means The calf is tied to a tree, not The calf ties a tree.

Ad arborem means to a tree.

Latin often uses ad + accusative to show movement toward something or attachment to something. In this sentence, it gives the idea that the calf is tied to the tree.

• ad takes the accusative
• arborem is accusative singular of arbor

So:

• arbor = tree
• arborem = tree, as the object of ad

In English, we simply say tied to a tree.

Because it follows the preposition ad, and ad takes the accusative case.

That is a very common Latin pattern:

• ad villam = to the house / toward the house
• ad viam = to the road
• ad arborem = to the tree

So arborem is not the direct object of ligatur; it is accusative because of the preposition.

Cuius means whose or of which.

It is the genitive singular form of the relative pronoun:

• nominative: qui, quae, quod
• genitive: cuius

Here it refers back to arborem (tree), so the phrase means:

• sub cuius umbra = under whose shade / under the shade of which

The genitive is used because the shade belongs to the tree.

Because the relative pronoun is being used to show possession, not to act as the subject.

Compare:

• quae = which or who, in the nominative feminine singular
• cuius = whose / of which, in the genitive singular

In sub cuius umbra:

• the main noun of the phrase is umbra = shade
• cuius tells us whose shade
• so Latin needs the genitive, not the nominative

Even though the antecedent is arborem (feminine singular), the form is cuius because the job of the word in its own clause is genitive possession.

Because sub here means under in the sense of location, and with that meaning it takes the ablative.

So:

• sub umbra = under the shade
• umbra is ablative singular

A useful rule:

• sub
  • ablative = position/location: under
• sub
  • accusative = motion toward a position under something

Here the calf is already staying there, so location makes sense.

Meridie means at midday, at noon, or sometimes simply in the heat of midday.

It is ablative singular of meridies.

Here it is an ablative of time when, which Latin often uses without a preposition.

Examples of the same idea:

• prima luce = at first light
• nocte = at night
• meridie = at midday

So meridie manet means he remains at midday or more naturally he stays there at midday.

Because Latin often expresses time when with the ablative alone.

English usually needs a preposition such as at or in, but Latin often does not.

So Latin says:

• meridie = at midday
• not necessarily in meridie or ad meridiem

This is a very normal Latin construction.

They go together as a phrase:

• cuius umbra = whose shade / the shade of which

More literally:

• cuius = of which
• umbra = shade

So the full prepositional phrase is:

• sub cuius umbra = under its shade / under whose shade

This is a relative phrase modifying arborem.

Latin word order is much freer than English word order because Latin shows grammatical function mainly through endings, not position.

So even though English would probably say:

• The calf is tied to a tree and stays under its shade at midday

Latin can say:

• Vitulus ad arborem ligatur, sub cuius umbra meridie manet.

A few things to notice:

• Vitulus comes first as the topic
• ad arborem stays close to ligatur
• sub cuius umbra is placed before meridie manet
• cuius is placed before umbra, as you would expect for whose shade

The order is natural Latin, even if it does not match normal English order.

Here manet means remains or stays.

• maneo often means remain, stay, continue to be in a place
• In some contexts it can be translated waits, but that is not the best sense here

So in this sentence:

• sub cuius umbra meridie manet = it stays under its shade at midday

The comma helps separate the two linked parts of the sentence:

1. Vitulus ad arborem ligatur
2. sub cuius umbra meridie manet

The second part adds more information about the same calf. Latin punctuation in printed texts is often editorial and can vary, but here the comma makes the structure easier to read.

So the comma is mainly a reading aid, not something essential to the grammar.

Yes, in natural English that is often the best translation.

Latin uses a relative construction:

• sub cuius umbra = literally under whose shade or under the shade of which

But English usually prefers:

• under its shade
• or under the tree’s shade

So grammatically cuius is whose/of which, but idiomatically its is often smoother.

Not necessarily in a real-world sense. Vitulus is grammatically masculine because that is the gender of the noun.

In Latin, grammatical gender and biological sex do not always match perfectly. But in this case, vitulus is a masculine noun meaning calf or sometimes specifically a young bull-calf, depending on context.

For reading the sentence, the important point is:

• vitulus is masculine singular nominative

That matters for agreement if adjectives or pronouns refer to it later.