Been playing Civ4:BTS. It's a Pangaea map... early in the game, I erradicated my closest neighbor, France. I ended up on the land-ward side of a peninsula, France on the sea-ward side. After destroying them I rebuilt my forces and started eying a near-by peninsula. Around now I attached the Great General Jean D'Arc to a Scout to serve as a mobile hospital. Germany had major stake and Mali had a minor stake. In addition to that, I was looking at some of Germany's territory that would cut me off from that peninsula. I decided to take it all; I marched up and took 3 German cities on the main land, before heading east to take three more. That left 2 German and 1 Mali city on the peninsula (dominating most of the coast), but I wrote up a quick peace treaty while rebuilding my military. A bit later I had my military there and invaded those remaining three cities, strengthening my more exposed cities after the resistance died down. From there, I declared peace again and Germany becomes Mali's vassal. I proceed to build up again and refocus my forces on my neighbor, the Holy Roman Empire. After he gets into a few minor wars that later escalate, I see my chance and declare war. I take 2 of his cities but leave a pretty big hole, and declare peace a few turns later. Rebuilding my forces yet again, Holy Rome becomes China's vassal. I later declared another war and took some more territory, but that'd be most of it for quite a while. Something interesting happened around the AD1700's; I was inducted into the Hindu Apostolic Palace and the first vote was to declare war on Mali (and vassal Germany). I was building up a strike force at that point; Mali had some tasty coastal cities that I wanted. One was a holy city, another their capital, and third just very populated. The vote goes through and war is declared; I hurry my navy to Mali to prepare for the invasion. First I take the holy city (Jewish & Christian), then the Capital (with oodles of Wonders), and finish it off with that populated city. I'm very happy with that war and mini-invasion; I crippled the Mali economy and research machine. While they still have great tracts of land and a lot of commerce (as well as production), they lost a source of >100 gold per turn and quite a few citizens.
My next move is a more proper invasion force; I want to permanently cripple Mali before I start to focus on the other super-power. It's kind of odd; there are three super-powers and a bunch of vassals now. Justian I and Hannibal make up the first and most prominent with 3 vassals, I make up the second with a single vassal, and Mansa Musa makes up the now-weakened third with a single vassal. I've got the second highest commerce (1st is Hann/Just), highest production, most soldiers, and most land. Pretty darn good for fighting wars the majority of the time! I'm just happy that my civ's not been bankrupt at any time; I've always been able to run 50% or higher Research.