Quantum possum, libros veteres lego.

Here quantum means as much as or to the extent that.

Grammatically, it is the neuter singular form of quantus, but in this kind of expression it is used adverbially rather than as an ordinary adjective. So quantum possum means as much as I can.

This is a very common Latin way to express degree or extent.

Possum is the 1st person singular present indicative active of posse, meaning to be able or can.

So possum means I am able or simply I can.

In quantum possum, the sense is:

• as much as I can
• as far as I am able

Latin usually does not need a separate subject pronoun when the verb ending already shows the person.

Both possum and lego are 1st person singular, so Latin speakers automatically understand the subject as I.

If you added ego, it would not usually mean just I in a neutral way. It would add emphasis, something like:

• I can
• I read

So the absence of ego is completely normal.

Yes. Lego can mean several things, including:

• I read
• I gather
• I choose
• I pick up

But Latin words are often clarified by context. Since the direct object is libros veteres (old books), the meaning I read is the natural one.

So in this sentence, lego is understood as I read.

Because libros veteres is the direct object of lego.

• libros is accusative plural of liber, meaning books
• veteres is accusative plural of vetus, meaning old

The adjective must agree with the noun it describes, so veteres matches libros in:

• case: accusative
• number: plural
• gender: masculine

So libros veteres means old books.

Latin adjective position is much more flexible than English adjective position.

In English, we normally have to say old books, not books old. But in Latin, both adjective-before-noun and adjective-after-noun are possible.

So libros veteres is perfectly normal Latin. It does not automatically mean something dramatically different from veteres libros.

Word order in Latin often depends on rhythm, emphasis, and style more than on strict grammatical necessity.

Yes, it is effectively a small subordinate clause used adverbially.

It tells you to what extent the action of lego happens:

• I read old books
• to the extent that I can

So quantum possum modifies the main action lego.

English often does the same thing with a clause like as much as I can.

The comma helps show the structure:

• Quantum possum = adverbial idea, as much as I can
• libros veteres lego = main clause, I read old books

So the comma marks a pause between the extent phrase and the main statement.

That said, punctuation in Latin is much less fixed than in modern English. Ancient manuscripts did not use punctuation in the same modern way. A printed Latin text may include the comma for clarity, but the grammar does not depend on it.

Because Latin word order is flexible, and fronting something often gives it emphasis.

By putting Quantum possum first, the sentence highlights the idea of extent right away:

• As much as I can, I read old books.

If you moved it later, the meaning would stay basically the same, but the emphasis would change.

So the current order gives prominence to the speaker’s effort or limitation.

Yes. Both possum and lego are in the present tense.

In Latin, the present tense can often cover both:

• simple present: I read
• progressive present: I am reading

The exact sense depends on context.

So lego could in theory be understood either way, but in a general statement like this, I read old books as much as I can is the most natural English rendering.