Need help improving map for this game!

[jesuisbenjamin]

OK, i had to make size readjustment (which took a lot of time since my computer had a hard time processing it). Now this map will be on A1 format and i will glue it to a six-fold cardboard to create the game board.
Because the original map's proportion did not fit the A standards, there are two margins left which i feel should be filled up with something. The most obvious filling would be an illustration or "logo" of the game. I have none so far. The game is called "Khan" (that's all i could come up with) which means "chief" and is a war/tribal word used widely Eurasia as a title for a tribal chief (there exist alternate forms as "Shan"). Khan is also a famous title of Genghis Khan, who was a mounted Mongol warrior who united the Mongols and held sway over central Asia. In the game the player with horses (from Mongolia in the historical mode) will have the first turn in attacks.
So it seems quite fit to me to have Mongol illustrations as a leitmotiv. I tried playing around with photos from movies which i manipulated in GIMP but i have nothing convincing so far. It's hard to find out what to put on the edges.
If you have any idea or suggestion, please let me know.
Thanks.