I'm playing as the Byzantines and I got into this epic(for me) war that lasted for 5 years. It started in 1427 as a war against the glorious almighty empire of Achaea(an OPM). Now They were allied and guaranteed by Venice, France, Milan, Aquilea, Wurttemberg, and Aragon. Those that joined were Aquilea, Milan, Wurttemberg, and France. I sort of wished that Aragon had joined 'cause they held Athens and that's all I needed to recapture Greece. They weren't really a threat land-wise(They had 3k total) but navally we were pretty much evenly matched.
Well there was only three theaters in the war: Naturally Achaea(France's only land battle), Aquilea, and Milan. Achaea was pretty much straight forward, a few months into the war they were gone, as I said France threw some troops in but it didn't change the outcome. Later I would completely destroy France's navy of 4 ships. After that France wasn't a threat. I signed MA treaties with Bosnia, Serbia, and Croatia, Which leads straight to the second Theater of the war: Aquilea. The Aquileans had 9k troops(in one stack) so I sent two of my standard 9k armies(3k cav 6k infantry) and in one battle I routed them and finished them off in the next battle. The sieging was the worst of it. In all I lost 6 regiments of infantry! After Aquilea fell I vassalized her(I had 23 infamy at the time). After that and armies replenished I signed MA treaties with Ferrara, Mantua, and Modena. Once I realized that Milan had 13k troops I brought up another army from Greece(I was building another by that point).
Once my armies were in Ferrara I moved one to Modena and two to Mantua to scout out the terrain and realized that Milan had their entire army in Brescia. I moved everything I had into the battle and after one follow up battle in Cremona I destroyed them. Then I spread out to siege. This siege didn't take as long as Aquilea, probably six months. In the end I took Parma. I wanted to Vassalize them too but no dice so I took Parma instead. Why? For my war against Aragon. I want Athens damn it! I realize that the war against Aragon will be decided navally. And the side closest to the action will have the edge and naturally Aragon will have that edge but Parma will lessen that edge. In the war I hope to nick The Baleares from them along with Athens. They'll be useful in future wars in the Western Med.
I think I'm getting close to my version of the Punic Wars...
That's pretty much where I'm at right now. It's Nov. 7, 1432. I'm having a blast with this game! Finally a game Paradox got right!