Archaeometallurgical characterization of a 16th century suit of armour made by Valentin Siebenbürger

•The archaeometallurgical characterization of a 16th century suit of armour was performed.•The thickness of steel sheet was adapted deliberately to the protective requirements of the individual elements of the armour.•Variations in thickness across the armour are highly consistent with the intended function of the individual parts, demonstrating the great skill of the master armourer Valentin Siebenbürger.•The suit of armour was made from three different grades of steel.•Non-metallic inclusions are typical for steel made during the early modern period. This helped us detect a subsequent restoration.