How the Medieval Cannon Changed Castle Design

Cannons and castles, at first glance, seem to be incapable of existing together in medieval warfare. Surely a wall is no match for a cannon? But when did cannons come about, and what were the first cannons like? Who was able to afford cannons? All will be answered in this video which looks at cannons, castles, and the forts that we see in the 1800s because I got a little bit carried away. Again.

Sources:
Own knowledge/previous research
Contamine, P., War in the Middle Ages (Oxford, 1984)