Aaargh! The polish nobles! The single unit I have yet to counter effectively! In my last russian campaign, they usually had 5 or more of them in each stack. I'm having the same problem with the hungarians now, I just lost over half my army in kiev because of them, the rest of their stack was town milita. They're fast, they have deadly javelins, and they fight EXTREMELY good in close combat. I sent my 7 experience general, one unit of alans and 2 units of merchant cavalry after a depleted unit of 8(!) polish nobles. I lost 15 men! Outnumbered 100:8, and I lost 15 men!

The best way to counter them IMO, is to get them passive, and then shoot them up. Unfortunately, they're never passive... When you go up against them, expect casaulties. There is no way to deal with them and only suffer a minimum of casualties. With units like crusader knights, you can bang them from multiple sides at once and with a couple of units, and the unit is gone with next to no casaulties. Try the same against the nobles, and you'll suffer at least 5 times as many casualties. The only advice I have, is to cover your losses. When going on a campaign, add a couple of extra units to deal with the losses...