The first eyeglasses were invented in Italy in the late 13th century, and were used to correct farsightedness. These early glasses also called "spectacles" are based on the late medieval archaeological find from Bergen Op-Zoom in the Netherlands, which dates from the 14th -15th century.
This medieval spectacles frame is made of 2 parts riveted together, in order to allow the spectacles to be opened or closed to fit the eyes of the user. The eyeglasses were simply clamped onto the nose and stretched behind the ears with straps attached to the small holes in the spectacle frame.
These medieval glasses are not including the lenses. The frames are slit on the underside so that they can be pulled apart a few millimetres to accommodate a pair of lens. A small plaited elastic serves as a fastener. Although once the lens are mounted, the ideal solution is closing the frame with a piece of thread, as was customary in the Middle Ages.
Each leg of the medieval spectacles measures 8.5 cm and is suitable for lenses with a diameter of 3.8 cm.
When inserting the lenses, the frame of the spectacle frame should only be pulled apart cautiously and with little force in order to avoid damage.