Cavalry affected by terrain?

[artur296]

Does the terrain affect cavalry or artillery in any way? I mean is it better to fight with cavalry on plains and artillery in mountains? Do they any bonuses?

[Kagemin]

There's only the general effects of terrain, usually giving a penalty to the attacker (rivers, mountains, forests...), many terrain types also affect the combat width, limiting how many units can fight at once (making it possible for small armies to hold up/defeat larger ones).

Cavalry gets a bonus for flanking. Since they are much more expensive than infantry you should have infantry to hold the lines and maybe 6-8 units of cavalry max (depending on technology level/ combat width).
Artillery can fire from the second rank so if possible you should have as much artillery as your current combat width allows.

No unit types get a bonus for certain types of terrain other than the army-wide effects I mentioned in the beginning.

[Xandurz]

Artillery also gives half of their defensive stat to the front row during defense, so having 2nd row fully filled will have all your army take less casualties.

[artur296]

I guess it's still better to fight with cavalry on plains since a larger combat width will allow more of then to fight and therefore better flanking.