Quinarius parvus est, sed victoriatus magnus est.

They are Latin nouns, and in this sentence they refer to types of Roman coins.

• quinarius = a quinarius
• victoriatus = a victoriatus

Grammatically, both are:

• nominative
• singular
• masculine

They are the subjects of their clauses.

They are both in the nominative singular.

You can tell because:

• they are the things being talked about
• they are the subjects of est (is)
• their endings, -us, fit the common pattern for second-declension masculine nominative singular nouns

So:

• Quinarius parvus est = The quinarius is small
• victoriatus magnus est = the victoriatus is large

Because adjectives in Latin must agree with the nouns they describe.

Since quinarius and victoriatus are:

• masculine
• singular
• nominative

the adjectives must also be:

• masculine
• singular
• nominative

So we get:

• quinarius parvus
• victoriatus magnus

This agreement is one of the most important features of Latin grammar.

They are adjectives, but in this sentence they are used as predicate adjectives.

That means they are linked to the subject by est:

• quinarius parvus est = the quinarius is small
• victoriatus magnus est = the victoriatus is large

This is different from using an adjective directly inside a noun phrase, like a small quinarius. Here the sentence is making a statement about the subject.

Because there are really two clauses:

• Quinarius parvus est
• sed victoriatus magnus est

Each clause has its own subject and its own verb est.

Latin can sometimes omit a repeated est when the meaning is obvious, but repeating it is completely normal and very clear, especially for learners.

Yes, sometimes Latin can leave it out if it is understood from the context:

• Quinarius parvus est, sed victoriatus magnus

This would still make sense.

However, the full version with both est forms is:

• clearer
• more straightforward
• very natural in beginner examples

So the sentence as given is a good standard model.

Because Latin does not have articles like English the and a/an.

So:

• quinarius can mean a quinarius or the quinarius
• victoriatus can mean a victoriatus or the victoriatus

Which one sounds best depends on context. English has to choose; Latin does not.

Sed means but.

It is a conjunction, specifically one that links two contrasting statements:

• Quinarius parvus est
• sed victoriatus magnus est

So the sentence sets up a contrast:

• one coin is small
• but the other is large

No. Latin word order is much freer than English word order because the endings show the grammatical roles.

So these can all mean roughly the same thing:

• Quinarius parvus est, sed victoriatus magnus est.
• Parvus quinarius est, sed magnus victoriatus est.
• Quinarius est parvus, sed victoriatus est magnus.

Some orders may sound more natural than others depending on emphasis, but the basic meaning stays the same.

That is a very common Latin pattern:

• subject + predicate adjective + est

So:

• quinarius parvus est
• victoriatus magnus est

Latin also allows:

• quinarius est parvus
• victoriatus est magnus

Both are correct. The version in your sentence is just a normal and simple way to say it.

In this sentence, they are best understood as common nouns naming coin types, so they are usually not capitalized in modern printed Latin.

Latin itself originally did not use upper- and lower-case letters the way modern languages do, so capitalization is mostly an editorial choice in modern texts.

So lowercase here is perfectly normal.

In a rough Classical Latin pronunciation:

• Quinarius ≈ kwi-NAH-ree-oos
• parvus ≈ PAR-woos
• est ≈ est
• sed ≈ sed
• victoriatus ≈ wik-toh-ree-AH-toos
• magnus ≈ MAG-noos
• est ≈ est

A rough full reading:

kwi-NAH-ree-oos PAR-woos est, sed wik-toh-ree-AH-toos MAG-noos est

Not grammatically. The sentence uses the positive degree adjectives:

• parvus = small
• magnus = large

So it literally says:

• The quinarius is small
• but the victoriatus is large

The contrast may suggest comparison in context, but Latin is not using explicit comparative forms here. If Latin wanted to say smaller or larger, it would normally use comparative adjectives such as minor or maior.

Each half follows the same pattern:

• subject
  • predicate adjective
    • est

So:

1. Quinarius = subject
   parvus = predicate adjective
   est = verb

2. victoriatus = subject
   magnus = predicate adjective
   est = verb

That makes the whole sentence a very useful beginner model for noun + adjective + est.