## Really Good. ##

I'd like to preface this with the fact that this is all conjecture and depends highly on the numbers of each side, but I'll base my answer on facts that we know.

Well, cavalry charges were largely ineffective against pikemen (who were employed heavily in the late medieval era), So your lance-wielding horsemen would face an extremely difficult challenge against a pike square. From wikipedia (Cavalry tactics): "Frontal assaults of heavy cavalry became considered ineffective against formations of spearmen or pikemen combined with crossbowmen or longbow archers." This points to the cavalry being highly ineffectual to your exact pike square with internal archers.

This, combined with the possibility that your shielded pikemen would have cover from the horse archers, points to the likelihood that the mounted combatants would fare extremely poorly against your pikemen.

Early Medieval historical examples of cavalry being defeated by pikemen/spearmen + archers:

 - the Battle of Stirling Bridge
 - the Battle of Bannockburn,
 - the Battle of Poitiers
 - the Battle of Crecy

In all of these examples, cavalry charges broke on pikemen OR cavalry was defeated by the bows of the archers, who were more effective on the ground than on horseback (From wikipedia, mounted archery): "Horse archery was usually ineffective against massed foot archery. The foot archers or crossbowmen could outshoot horse archers and a man alone is a smaller target than a man and a horse."

So, all things being equal it would appear based on historical examples and analysis, your pikemen and archers would likely fare quite well.