If you have VI I believe churches etc. give morale bonus. What I did as Russians, high period, I built a cathedral and so on in one settlement producing uber-halberdiers, then produced pavise arbalesters in another one. I managed to make a quite decent army before the horde came, by rushing and crushing most of the Polish and all rebels. I must say the halberdiers with upgraded morale are one of the best units in M:TW singleplayer, plus they're cheap in upkeep.