by Becq
As an FYI to others reading this (probably too late), the spoiler boxes above don't refer to the usual box unlocks; they are all "Box 5" unlock spoilers.@Jim, your question for Box 5 above: it says this in one of the unlocked rules on p.16 in your rulebook: [o]"pick an entry from the tomb map". You can choose any entry number on the map.[/o]
Also, the *only* key to ending the game is what's covered in the "Box 4 and 6" spoilers above. Everything else is interesting and/or useful and/or a side quest (for example, there are several other hints that can allow you to infer the info from "Box 6"), but not strictly necessary.
In any case, all I can think is that it was dumb luck you missed the "Box 4" rules. There are two advisors that should have given you that hint.
Here are their ranks, if you need the spoiler:
[o]18 and 27[/o]
It's possible you've seen their numbers but haven't looked further.
Here are which advisors they are, if you need the spoiler:
[o]18: Historian
27: Patriot[/o]