Probably a flanged punch created the bosses to a uniform size and depth, although no contemporary tool has been found to accomplish this. The embossing would probably require the work piece to be supported, conceivably by a bed of pitch or lead. Some eye-judgement was required, which is revealed in the detail of the spacing of the bosses. As the craftsman came to complete a ring, the spacing would be changed slightly so as to ensure an even design and make the starting place inconspicuous. The shields show a high degree of accomplishment and, given the degree of similarity, it is likely that all were made in the same workshop by a few craftsmen.