heavy cavalry engaging heavy cavalry

[Dan Howard]

Another great victory of heavy lancers cavalry:

None of these examples are any use without the context. How do you define "victory"? Why were they defeated? Were they taken by surprise? Were they hit from the flank or rear? How did the terrain help? Were any diseases spreading through the camp? What percentage of the troops was experienced and well provisioned? What was the weather like?

FWIW all of the great powers of Europe tried to maintain regiments of heavy cavalry, at great expense, right throughout the so-called "age of gunpowder". This wouldn't have been done if they didn't serve a very important function. On the flip side, the 14th century saw a change from cavalry dominated battles to infantry dominated ones. It was around this time that an experienced, disciplined formation of infantry started to get the upper hand over heavy cavalry. The best book on the subject is DeVries' Infantry Warfare in the Early Fourteenth Century.