What is exactly the point of sneaking into a castle? When I discovered that pulling a siege by myself wouldn't work, I noticed that I had the option to sneak into the castle. I can't even get them to go somewhere else. I tried waiting 5 days for them to do something but to no avail, they continue standing there. I can't take on a castle by myself (partly because I have no idea how to make my men move the siege tower, and partly because I simply don't have enough men) so this is rather problematic. They are just sitting beside the castle and the rest of the army didn't follow. Only problem is, they aren't doing anything.
So I decided to try my luck at commandeering the war effort, and I convinced the Marshal and the King to come siege a castle with me.