Amica ex Neapoli epistulam ad Romam miserat et veniam pro mora petebat.

A helpful way to parse it is:

• Amica = the subject, a/the female friend
• ex Neapoli = from Naples
• epistulam = a/the letter (direct object)
• ad Romam = to Rome
• miserat = had sent
• et = and
• veniam = forgiveness / pardon
• pro mora = for the delay
• petebat = was asking / asked

So the structure is:

[Subject] [from where] [what] [to where] [had sent] and [forgiveness] [for the delay] [was asking].

Latin often makes more sense once you identify the cases and the two verbs first.

Amica is the feminine form of amicus/amica, meaning friend.

Here it is:

• nominative singular
• feminine
• the subject of the sentence

So it means a female friend or the friend, depending on context.

A native English speaker may wonder whether it means girlfriend. It can in some contexts, but by itself it usually just means female friend.

Latin has no articles. It does not have separate words for a/an or the.

So:

• amica can mean a friend or the friend
• epistulam can mean a letter or the letter

You decide from context which is more natural in English.

Ex means out of / from and normally takes the ablative case.

So:

• ex Neapoli = from Naples
• Neapoli is ablative singular

A learner may notice that place names sometimes behave specially in Latin. That is true, but in this sentence the simplest thing to see is:

• ex = from
• Neapoli = ablative after ex

Ad means to / toward and takes the accusative case.

So:

• ad Romam = to Rome
• Romam is accusative singular

This shows movement or direction toward a place.

A learner might also have seen that with names of towns and cities Latin can sometimes use the accusative without a preposition for motion toward a place, so Romam by itself can also mean to Rome. Here, ad simply makes the direction very explicit.

Because it is the direct object of miserat.

She had sent what?

• epistulam = the letter

That is exactly what the accusative often does in Latin: it marks the direct object of the verb.

Miserat is pluperfect active indicative, third person singular, from mittere (to send).

It means:

• he/she/it had sent

So here:

• amica ... miserat = the friend had sent

The pluperfect places the action before another point in the past. In a larger story, this often means the letter had already been sent before the next narrated event.

Petebat is imperfect active indicative, third person singular, from petere.

It means something like:

• was asking
• kept asking
• sometimes simply asked, depending on context

Why the different tense?

• miserat presents the sending as a completed earlier action
• petebat presents the asking as ongoing, in progress, or backgrounded in past time

So the sentence gives a nice contrast:

• she had sent the letter
• and she was asking pardon for the delay

This kind of tense contrast is very normal in Latin narrative.

Literally, it means she was seeking pardon.

• veniam = pardon, favor, forgiveness
• petebat = was seeking / asking for

Together, veniam petere is a common expression meaning:

• to ask forgiveness
• to beg pardon

So this is not just random vocabulary placed side by side; it is a standard Latin idea.

Pro mora means for the delay or because of the delay.

• pro is a preposition that takes the ablative
• mora is ablative singular of mora, meaning delay

So:

• pro mora = for the delay / on account of the delay

This tells us what she was asking pardon for.

Because Latin often omits words that are obvious from context.

The subject of miserat is amica, and after et the same subject is still understood:

• Amica ... miserat et [amica] veniam ... petebat

Latin does not need to repeat amica if the meaning is already clear.

English can do this too:

• The friend sent a letter and asked forgiveness

We do not need to repeat the friend in the second half.

Yes, the word order is perfectly normal.

Latin has more flexible word order than English because the endings show how words function:

• amica = subject
• epistulam = direct object
• Romam = destination
• mora = ablative after pro

That means Latin does not rely as heavily on word order to show meaning.

This sentence is actually fairly learner-friendly in its order:

• subject first
• then place phrases and object
• then the first verb
• then the second clause

A different order could still be grammatical, but this one is quite clear.