One of the most spectacular, if fearsome looking, Roman medical instruments is the vaginal dilator or speculum (dioptra). It comprises a priapiscus with 2 (or sometimes 3 or 4) dovetailing valves which are opened and closed by a handle with a screw mechanism, an arrangement that was still to be found in the specula of 18th-century Europe. Soranus is the first author who makes mention of the speculum specially made for the vagina. Graeco-Roman writers on gynecology and obstetrics frequently recommend its use in the diagnosis and treatment of vaginal and uterine disorders, yet it is one of the rarest surviving medical instruments. Specula are large and readily recognizable and should not have suffered the same degree of destruction as thin instruments, such as probes, scalpels and needles. As a source of bronze, however, they may have been more subject to recycling than the smaller instruments.