Trepanned Bronze Age skull, 2200-2000 BC.
© Science Museum / Science & Society Picture Library
This skull, excavated from Jericho in Palestine, shows four trepanned holes. Trepanning was the ancient practice of cutting holes in the skull, probably with the intention of releasing evil spirits or demons from the mind, which were believed to be responsible for causing mental problems or headaches. Drilled holes were roughly circular, whereas knife-cut ones were usually square-shaped. That this individual survived the proces can be deduced from the fact that the bone shows signs of healing.