Historic Battles?

[Orda Khan]

You mean the little crossed swords, site of famous battle? From my experience these appear after large battles, especially when won against the odds

.....Orda

[Lord Fluffy]

If you mean the named historical battles, these are not part of the grand campaign. There's an option in the menus for single play for historical battles, much like custom battles.

[gingergenius]

With me, they have to be huge battles. There's a good chance if you kill over 1000 of your enemy. And a good chance if you are seriously outnumbered and still win.

One certainty: You fight two armies - one attacks from behind and one from the front. Kill over 1000 and win this battle and its certainly a famous battle. You get a pair of crossed swords and a note saying when the battle was, and who the winning and losing generals were.

In my current campaign I've got to 1200 on 0.5 timescale, and fought in 4 famous battles myself. On the land I've seen there's also a pair of crossed swords for a battle between a Polish and Rebel army.