Iron, knife, scramasax

This fighting-knife, or 'seax', has a blade made with a technique known as 'pattern welding'. Bars of iron and steel were twisted and hammer-welded together while white-hot, welded to a steel edge and ground and polished. The twisted bars produce a herringbone or snake-like pattern visible on the polished surface. Pattern welding made blades that were resilient but sharp, so was especially useful in swords and other valuable weapons. The technique was popular from the 800s to the 1000s, but was superseded by better methods of steel production in the 1100s.