On meaning and syntactic structure of "usque eo quoad his sex annis"

Question

I am reading the Latin version of the Little Prince, namely Regulus, translated by Auguste Haury. In the beginning of Chap. 2, I saw this sentence a little hard for me:

Sic aetatem solus egi nec quisquam praesto fuit quocum vere colloquerer usque eo quoad his sex annis in Garamentum solitudine destitutus jacui.

There is already a main verb egi in front, so jacui requires a conjunction, here I think quoad. In Ketherline Woods' English version, the same sentence is translated as

until I had an accident with my plane in the Desert of Sahara, six years ago.

But I don't know how usque eo quoad his sex annis can be understood like this: I don't get the meaning of eo and quoad here.

How to parse the syntactic structure of this sentence?

Answer 1

Quoad here is a correlative of usque eo. i.e., thus/so far (usque eo) until/that (quoad).

syntactically it is like the more common (usque) adeo/eo... ut/quo/dum/donec. like this Seneca's example

Haec usque eo animum Socratis non moverant ut ne vultum quidem moverint [so far (usque eo)... to the extent that (ut)...

Here another example from Cicero:

atque hoc scitis omnes, usque adeo hominem in periculo fuisse quoad scitum est Sestium vivere (And you are all aware that he was in danger [so long] until it was ascertained that Sestius was alive; (Yonge) .

It is somewhat unusual (and probably makes it more difficult to parse) that in this passage from Regulus quoad is right next to the eo, whereas most of the examples do have the "antecedent" between them. In fact, there is no (usque) eo quoad in PHI, and only one usque adeo quoad (but usque eo ut is more common); Thus, here, the usque eo relates to what comes before (aetatem ... colloquerer), so like the example from Cicero it should be understood: "I was without anyone to talk to until I was laying abandoned six years ago"