An attempt was made to evaluate the disputed authenticity of a sallet (a light helmet) allegedly from the late 15th century. Metallographic examination of the microstructure revealed only minor amounts of non-metallic inclusions. Form and distribution of slag inclusions led to the conjecture that the material of the sallet probably is of recent origin, at least more recent than the 18th century. A comparison with the microstructure of a steel breast armour plate definitely of medieval origin corroborated the conjecture.