13th Century Great Pot Helm with Brass Crown and Cross Medieval HelmetMedieval 13th Century Great Helmet of Castile Fernando III Middle Ages Helmet Sca Larp Reenactment Wearable Costume. In the course of the 13th century, the crusader helmet developed further and finally became the true cylindrical bucket helmet, as we know it from numerous illustrations and finds from the Middle Ages. This large pot helmet completely enclosed the head the same on all sides and enjoyed great popularity throughout Central Europe.