>Mission #8 is "Rescue 10 Peasants".

>I finally managed to extinct the opposition but when I reached the
>prison, all prisoners have died. Is there a time limit (eg. I must
>have freed them before year 40) ? Or did they die because of loss of
>food ?

No, there's not really a fixed time limit. But as you have seen, prisoners
a) won't live forever and b) weren't necessarily captured as babies. :) In
other words: Rescue them ASAP! Extincting an opponent is generally nice,
but if the briefing reads "Rescue x people", then grab your army and run!

Although it can help if you take over buildings that are in your way (hint,
hint).