Trouble with Cicero's Pro Archia

I am trying to translate Cicero’s Pro Archia but it is very hard, he doesn’t half ramble.

In the end of paragraph 23:
http://www.forumromanum.org/literature/cicero/arch.html#23

It says:

quod cum ipsis populis de quorum rebus scribitur, haec ampla sunt, tum eis certe, qui de vita gloriae causa dimicant, hoc maximum et periculorum incitamentum est et laborum.

I am looking at the english translation and I do not get how they were able to arrive at it without breaking grammatical rules and adding additional info:

Because, as this is always an ample reward for those people whose achievements are the subject of writings, so especially is it the greatest inducement to encounter labours and dangers to all men who fight for themselves for the sake of glory.

Could someone analyse this sentence in detail and provide a more literal translation? Because I do not get it at all. For example:

If “scribitur” refers to “quorum rebus” (whose achievements are the subject of writings), should it not be “scribiuntur” because it is plural (i.e. more than one achievement)?

Where is the word “reward” eluded to in the original Latin? It seems to just say “haec Ampla Sunt”, meaning their achievements are great, but where is the ample reward?

What does ‘tum eis certe’ actually mean translated literally? And where is it referred to in the translation?

I assume that ‘maximum incitamentum est’ must mean “it is the greatest inducement”, is that correct? If so, where is the verb “to encounter” in the original Latin? Both ‘labors’ and ‘dangers’ are in the genitive form, but genitive of what?

In the next paragraph, it says:

Sulla cum Hispanos donaret et Gallos, credo hunc petentem repudiasset: quem nos in contione vidimus

This is translated as:

Sulla, when he was giving it to the Spaniards and Gauls, would, I suppose, have refused him if he had asked for it! a man whom we ourselves saw in the public assembly

How can one know that “quem” refers to “a man”? Which man does it refer to anyway? Is it Sulla, or the poet? And would it not make more sense if “quem” refered to “petentem”, i.e. the request/petition that the poet may have made to Sulla and is now presented before the public assembly?

Because not only for those people about whose affairs/deeds it is written [/whose deeds are written about],
these things are important/horourable/exalted,
but also certainly for those,
who struggle at the risk of life [/their lives] for the sake of glory
this is the greatest inducement
both of/for taking risks and of/for hardships.



Sulla, when he was granting the Spanish and the Gauls, I believe this petitioner [/this man petitioning] he would have turned down, he whom we ourselves saw in an assembly…

De eo quem pronomen refert, et Latinè et Anglicè res hîc ambigua est; contextus autem Sullam indicat, sicut ordo verborum in quo “repudiasset” et “quem” annexa sunt.

In English (“he”) and in Latin (“quem”), it’s ambiguous to whom it refers here, but the context points to Sulla, as does the proximity of “repudiasset” and “quem”

No, look at the follow on (that gives the context): “he whom we ourselves [or I myself] saw at an assembly, when a bad poet from the crowd presented to him a small book, because he had made epigrams on him, only with alternate lines a little too long…”

Minimé! Quod sequitur (contextum parans) inspice : “quem nos in contione vidimus, cum ei libellum malus poeta de populo subjecisset, quod epigramma in eum fecisset, tantummodo alternis versibus longiusculis…”

He rambles persuasively. And he’s being sarcastic here when he proposes Sulla would have passed over Archias, so translate “credo” as “I suppose” instead of “I believe”.

Blanditer pererrat. Etiam de repudiatione Archiae suppositâ à Sullâ, dicace modo Cicero arguit. Non ità anglicè “I believe” sed “I suppose” pro “credo” verbo.