My most heroic and epic battles were in Medieval (I) Total War (with Viking Expansion). I was Russia, preparing my kingdom for the arrival of the Mongols. If you have ever played Medieval Total War and experienced the Mongols there you know FEAR. Their armies were massive, several fullstacks full of their superior heavy cavalry (kinda like cataphracts), innumerable heavy archers, gunmen and quite some artillery. In Medieval Total War, the AI was quite good, especially in battles. Usually I would retreat until their armies were thinned out over a large area, however this time I decided to risk it all in an all-or-nothing-battle. So I massed my armies, 3 fullstacks of mainly heavy spearmen and arabalests plus some medium steppe cavalry and boyars (basically armoured horse archers). The battle was a slaughter. It was quite close but then I managed to kill their Khan and their whole army broke apart. It was one of the bloodiest battles I've ever had.
However my most glorious battle was against the Turks. In the very same campaign the Turks had been eradicated by the Byzantines and the Egyptians. After I had survived the Mongol invasion, I left one fullstack in Khazan to guard my border with Egypt; the rest of the army was either put in garrisons throughout my kingdom or disbanded, as the immense costs of maintaining such a large army drained my treasury and nearly bankrupted me. So I thought that I had survived the worst danger. Then all of a sudden the Turks reemerge... in Khazan... with 5 fullstacks. I thought I was done for sure but decided to try to kill as many of their troops as possible so my empire would not be comlpetely overrun. Same basic strategy as with the mongols. Only this time I pulled a desperate suicide move. I charged with all my spearmen into their line, trying to open up a gap in their lines so I could try to kill the Sultan. It worked. As soon as their Sultan was dead, the armies fell apart. I slaughtered about 6000 to 7000 enemy troops with my one fullstack. It took me nearly twenty minutes to rout all their incoming reinforcements who basically routed as soon as their entered the battlefield. The battlefield was a sea of fleeing men.