The earliest fetters found in archaeological excavations date from the prehistoric age and are mostly of the puzzle lock type.
These were widely used in medieval times, but their use declined when mass production made the manufacture of locks built into restraints affordable.
The shackle consisted of an iron band supported by braces which went down and under the prisoner's foot.
The shackle's weight hobbled the prisoner's movements to prevent escape, and long-term use would cause severe injury to the wearer.
[5][6] The countries that continue to make prisoners wear fetters long-term now tend to manufacture their own restraints.