Typically, medieval (Because I like them the most) Armourers had 4-horned anvils, and did most of the plate shaping of the flat steel, cold. They used heat only for tight bends and welding some parts together.
Here are a few pictures of the medieval armourers at work.
If you are curious about the 2 bellows in the one picture (the medieval style), don't hesitate to ask!:cool: