Cum sol oritur, lumen per fenestram in cubiculum intrat.

Because cum can be either:

• a preposition meaning with when it is followed by a noun in the ablative, or
• a conjunction meaning when, since, or although when it introduces a clause.

Here, cum sol oritur is a full clause with a subject (sol) and a verb (oritur), so cum is a conjunction and means when.

Oritur is the 3rd person singular present indicative of orior, oriri, meaning to rise.

It is a deponent verb, which is an important Latin feature:

• it has passive-looking forms
• but an active meaning

So although oritur looks passive, it means he/she/it rises, not is risen.

Since the subject is sol (the sun), oritur means the sun rises.

Sol is the subject of oritur, so it is in the nominative case.

Its basic dictionary form is sol, solis (masculine), and the nominative singular is simply sol.

So:

• sol = the sun as subject
• oritur = rises

Together: sol oritur = the sun rises

Lumen is also in the nominative singular, because it is the subject of intrat.

The main clause is:

• lumen ... intrat = the light enters

So even though English often puts important information later, Latin shows the subject by its case ending, not mainly by position.

Lumen is a neuter noun:

• dictionary form: lumen, luminis

Its nominative singular is lumen.

Because per is a preposition that takes the accusative case.

So:

• fenestra = nominative or ablative singular
• fenestram = accusative singular

Since per means through, Latin requires:

• per fenestram = through the window

This is something to memorize with the preposition:

• per + accusative

Because in can take either the accusative or the ablative, depending on the meaning.

• in + accusative = into / motion toward
• in + ablative = in / inside / location

Here the light is entering into the room, so Latin uses motion toward a place:

• in cubiculum = into the bedroom
• in cubiculo would mean in the bedroom or inside the bedroom

Since the verb is intrat (enters), the accusative makes sense.

Latin has no articles like English the or a/an.

So a noun like sol can mean:

• the sun
• a sun

and fenestram can mean:

• the window
• a window

The exact sense usually comes from context. In this sentence, English naturally uses the:

• the sun
• the light
• the window
• the room

But Latin does not need separate words for those.

Latin word order is much more flexible than English word order because Latin uses case endings to show each word’s role.

So Latin can place words in different orders for:

• emphasis
• style
• rhythm
• clarity

In this sentence, putting intrat at the end is very natural Latin. It lets the sentence build toward the action:

• Cum sol oritur = when the sun rises
• lumen per fenestram in cubiculum = the light through the window into the room
• intrat = enters

English depends more on word order; Latin depends more on endings.

Not here. This sentence uses the indicative: oritur.

That is because this is a straightforward temporal use of cum, meaning when in a general or factual sense.

Latin often uses:

• cum + indicative for simple time: when
• cum + subjunctive for circumstances like since, although, or more literary background context

So here:

• cum sol oritur = when the sun rises

There is nothing unusual or hidden about the mood in this sentence.

The present tense here describes something general, habitual, or regular:

• when the sun rises, the light enters the room

Latin often uses the present for statements of repeated or normal action, just as English can say:

• When the sun rises, light enters the room.

It does not have to mean that it is happening only right now. It can describe what generally happens.

They do, but they express different kinds of movement.

• per fenestram = movement through something
• in cubiculum = movement into a place

So the sentence shows the path very clearly:

1. the light goes through the window
2. then it goes into the room

Latin often uses prepositions very precisely in this way.

Yes, in Latin lumen can mean:

• light
• daylight
• lamp-light
• sometimes more figuratively brightness, glory, or even source of enlightenment

But in this sentence, because of the sun, the window, and the room, the meaning is clearly physical light or daylight.

So lumen here is simply the light coming in.

Latin usually does not use a separate subject pronoun unless it is needed for emphasis or contrast.

The verb ending already tells you the subject is 3rd person singular:

• oritur = he/she/it rises
• intrat = he/she/it enters

And the nouns sol and lumen are already present as subjects, so there is no need for an extra pronoun.

Latin is often more economical than English in this way.