ancientpanoply:

The Viksø helmets are a pair of horned bronze helms found in a Danish bog dated near 900bc. They are too thin to have provided useful protection, so they are probably ceremonial items.

Info and 3D view on the Danish National Museum:

http://natmus.dk/en/historisk-viden/danmark/moeder-med-danmarks-oldtid/the-bronze-age/the-viksoe-helmets/

Horns!!