Great helm

The barreled style was used by knights in most West European armies between about 1210 to 1340 AD and evolved into the frog-mouth helm[1] to be primarily used during jousting contests.

In its simplest form, the great helm was a flat-topped cylinder of steel that completely covered the head and had only very small openings for ventilation and vision.

Knights usually wore the great helm over a mail coif (hood) sometimes in conjunction with a close-fitting iron skull cap known as a cervelliere.

Its biggest drawback is the square edges, that crumple very easily under blunt force trauma, and poor ventilation and air circulation.

Although visor slits are usually only some 20–30 mm wide, they do not greatly restrict the field of vision as they are very close to the wearer's eyes to reduce parallax.

13th century German great helm with a flat top to the skull.
Great helms were worn with cloth and fiber padding on the inside, here shown removed from the helmet.
Funeral helmet of the von Pranckh family, 14th century, with the crest of two bullhorns. ( Side view )