sequence of events?

[Ironhawk]

In addition to not being able to build structures while under siege, you cannot destroy them. Something to keep in mind if you are doing a scorched earth strategy and think you might get caught up in a siege

[Endoperez]

If you try to recruit units while under siege and you don't manage to break it, the money is wasted. If you do break the siege, then the units of the Last turn are recruited as they normally would.