Earlier generations of Eastern European cast copper-alloy lamps were assembled using rectangular prongs called tenons. In later lamps, the tenons disappeared and only screws were used. The use of all-tenon or tenon-and-screw construction should be broadly dated from the eighteenth century, by which time production apparently began, to the first half of the nineteenth century. Lamps assembled with screws alone can be roughly dated from the mid-nineteenth until probably the early twentieth century.