This period covers fantasy literature and cinema, as well as mythology and folklore. Heroic armies of Dwarves, Elves and Men can battle the hordes of Orcs and Trolls.
Possible battles in this period are the battle of the Five Armies (The Hobbit), Pelennor Fields (The Lord of the Rings), Battle for Tyrsis (The Sword of Shannara), The Riftwar (The Magician) or Thull Mardu (The Belgariad). You could also create your own armies, perhaps based on a current role-playing campaign.