Helmets-First off, they didn't have horns.
Viking helms were typically a standard spangle helm, a simple dome helmet with
a nose piece and occasionally a spectacle face covering. Some helms would have
had chain-mail connected to cover the neck. They were also expensive so not everybody had one. Most would go without or settle for some kind of leather
cap.
Leather- as chain mail is bloody expensive the common soldier would likely opt for leather armor with padding underneath. Leather would protect against most cuts and the cloth underneath would soften blows. Leather armor also offers the benefits of speed and agility in combat.
Mail- Chain mail was typically a shirt of iron rings joined together more often than not by welding of the ringlets.
Leather- as chain mail is bloody expensive the common soldier would likely opt for leather armor with padding underneath. Leather would protect against most cuts and the cloth underneath would soften blows. Leather armor also offers the benefits of speed and agility in combat.
Mail- Chain mail was typically a shirt of iron rings joined together more often than not by welding of the ringlets.