For as long as there have been swords, there has existed the need for the fencer to hone his skill without killing or maiming his training partner. Safe, durable, and inexpensive foils only became widely available in the early 20th century-- especially after the manufacturing advances that came along with the First World War. But up until then, the waster was your best bet for less-than-lethal training.
A waster is, for all intents and purposes, a wooden sword. Just as there are a bunch of swords out there, wasters come in all shapes and sizes. A waster can be hardly more than an over-glorified dowel, or a perfectly balanced, finely shaped facsimile of the real deal. Modern wasters are most often made from hardwoods such as oak or hickory.
Pretty much every culture that had the sword had the waster. Egyptian wall paintings depict a form of fencing that utilizes a waster and reed shield strapped to the forearm. There are numerous accounts of Roman soldiers training with wooden gladii. The Japanese bokken and shinai are perhaps the most widely recognizable wasters.