Kettle hat - a conical helmet wrapped up in a bowl-shaped hat - hence the name. Popular among infantry and knighthood soldiers.
Kettle hat is a helmet that dates back to ancient times, but it was also very popular throughout the Middle Ages. It was worn by French horsemen, who gave rise to European knighthood. Later on it was popular mainly among infantry because it was cheap to produce and it protected against blows from above - i.e. by a rider or during a siege when storming the walls. They appeared in various shapes and sizes. One of the types of this helmet gave rise to hussar helmets.