This helmet is part of a suit armour with similar decorative grooves as on the helmet’s skull.
This type of armour is often referred to as Maximilian armour (after the Holy Roman Emperor Maximilian I). The bellows visor on the helmet is also characteristic of this type of armour.
It was thought, during the 19th century, that the helmet had belonged to King Johan I of Sweden (who died in 1222) but it was later revealed that the helmet had in fact been made in Germany around 1510.