The steelyard is an ancient Roman scale whose operation is based on the principle of levers. It consists of a long graduated arm with two different units of measurement engraved on it on which the weight, called “roman”, slides. The scale has a fixed fulcrum with a balance indicator and a plate on which the merchandise rests. To obtain the weight measurement, the roman is moved along the graduated arm until it reaches the balance that indicates the weight of the merchandise. The scale could be supported by hand for smaller weights or fixed to a stable support for larger weights. Thanks to its ease of transport, use and its immediacy and accuracy in reading, the steelyard was one of the most popular weighing instruments before the advent of automatic scales.