thanks for the input. The objective is to capture the "ruined tower", which I think I have done. But it is probably something simple I am overlooking, an unexplored area of the map, or something......I will get back to this game, if I can tear myself away from Age of Wonders!
DarrkPhoenix: As has been mentioned there's no need to capture the capital. In Disciples 1 capturing a capital is quite difficult, and there isn't a single mission in any of the campaigns where it's required. In Disciples 2 there's a single mission where you're required to capture a capital (if memory serves it's the final Clans mission), but in that one they actually had to toss in a beefed up, scripted enemy just before the capital because by that point in the campaign your army is so powerful that capturing a capital is pretty easy.