User blog comment:RSV 123/Chatrapati Shivaji vs. Attila the Hun/@comment-5232784-20120804032536/@comment-5232784-20120804040153

Because a Musket would be something totally new, something that the Horse wasn't prepared for. Just like the noise of cannons or burning, squealing pigs can panic elephants unaquianted with such horrors, a horse, even a war horse, just might be spooked by gunfire upon hearing it for the first time. However, this is only a possibility, and even with this the better armor and sword of Shivaji should still win him the fight.

And if Shivaji is mounted, his horse, unlike that of Atilla's, would be used to gunfire, even cannon fire, and therefore not given to spook with musketfire.